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tetsuo-pulse — Tetsuo Socket Library | Kitploit
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GitHub7etsuo/tetsuo-pulse

tetsuo-pulse

Tetsuo Socket Library

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Socket Library Logo

License: MIT Coverage

Socket Library

Hinweis zum Reifegrad: Diese Bibliothek ist funktionsfähig und gut getestet, aber neu veröffentlicht. Sie ist geeignet für Entwicklung, interne Werkzeuge und kontrollierte Umgebungen. Die Produktionsbereitstellung mit nicht vertrauenswürdigen Netzwerkeingaben sollte warten, bis die Codebasis mehrere Monate reale Härtung erfahren hat.

Hochleistungsfähiges, ausnahmegesteuertes Socket-Toolkit für POSIX-Systeme. Bietet eine saubere, moderne C-API für TCP, UDP, Unix-Domain-Sockets, HTTP/1.1, HTTP/2, QUIC, WebSocket und TLS/DTLS mit umfassender Fehlerbehandlung, Zero-Copy-I/O und plattformübergreifender Ereignisabfrage.

Funktionen

Kernnetzwerk

  • TCP-Stream-Sockets – Voll ausgestatteter TCP-Client/Server mit Scatter/Gather-I/O
  • UDP-Datagramm-Sockets – Verbindungslose und verbundene Modi mit Multicast/Broadcast
  • Unix-Domain-Sockets – IPC-Sockets mit Peer-Anmeldeinformationen und Dateideskriptorübergabe
  • TLS 1.3-Unterstützung – Modernes TLS mit SNI, ALPN, Sitzungswiederaufnahme, CRL/OCSP, Zertifikat-Pinning, Certificate Transparency (CT), kTLS-Offload, 0-RTT-Frühdaten, KeyUpdate
  • DTLS 1.2+-Unterstützung – Sicheres UDP mit Cookie-Austausch zum DoS-Schutz, Sitzungs-Caching, ALPN

HTTP-Protokollstapel

  • HTTP/1.1 – Tabellengesteuerter DFA-Parser (RFC 9112), Chunked-Encoding, Request-Smuggling-Verhinderung
  • HTTP/2 – Binäres Framing, Stream-Multiplexing, Flusskontrolle, Server Push (RFC 9113)
  • HPACK – Header-Kompression mit statischen/dynamischen Tabellen, Huffman-Codierung (RFC 7541)
  • QPACK – HTTP/3-Header-Kompression (RFC 9204), Zwei-Stream-Architektur, Blockiertes-Stream-Management
  • HTTP-Client – Verbindungspooling, Authentifizierung (Basic/Digest/Bearer), Cookies (RFC 6265)
  • HTTP-Server – Ereignisgesteuerte Anfragebearbeitung, Keep-Alive, Graceful Shutdown

QUIC-Transport

  • RFC 9000-konform – Vollständige QUIC v1-Transportprotokollimplementierung
  • Verbindungsverwaltung – Connection-ID-Rotation, Zustandsloser Reset, Adressvalidierung
  • Stream-Multiplexing – Bidirektionale und unidirektionale Ströme mit Flusskontrolle
  • Verlusterkennung – RFC 9002 Überlastregelung und Verlustwiederherstellung
  • Pfadmigration – Nahtlose Verbindungsmigration bei Netzwerkwechseln
  • 0-RTT-Wiederaufnahme – Schnelle Wiederverbindung mit Frühdaten-Unterstützung

QUIC-TLS (RFC 9001)

  • Paketschutz – AEAD-Verschlüsselung (AES-128-GCM, AES-256-GCM, ChaCha20-Poly1305)
  • Header-Schutz – AES-ECB/ChaCha20-Maskenerzeugung für Paketnummernverschlüsselung
  • Schlüsselableitung – HKDF-basierte Initialgeheimnisse aus Client-DCID, Handshake/Verkehrsschlüssel
  • Schlüsselaktualisierung – Schlüsselphasenbit-Rotation mit AEAD-Vertraulichkeitsgrenzen (RFC 9001 §6)
  • Retry-Integrität – AEAD-Tag-Überprüfung für Retry-Pakete (RFC 9001 §5.8)
  • Transportparameter – TLS-Erweiterung (Typ 0x39) für QUIC-Konfigurationsaustausch

QPACK (RFC 9204)

  • Header-Kompression – HTTP/3-Header-Kompression zur Vermeidung von Head-of-Line-Blocking
  • Zwei-Stream-Architektur – Getrennte Encoder- (0x02) und Decoder-Ströme (0x03)
  • Dynamische Tabelle – Absolute Indizierung mit encoder- und feldrelativen Schemata
  • Statische Tabelle – 99 vordefinierte Einträge (RFC 9204 Anhang A)
  • Zustandssynchronisation – Abschnittsbestätigung, Stromabbrechen, Einfügezählererhöhung
  • Blockiertes-Stream-Management – Konfigurierbare Grenzen für blockierte Ströme mit SETTINGS-Aushandlung

WebSocket

  • RFC 6455-konform – Vollständige WebSocket-Protokollimplementierung
  • permessage-deflate – Kompressionserweiterung (RFC 7692) über zlib
  • Inkrementelle UTF-8 – DFA-basierte Textframe-Validierung
  • Auto-Ping/Pong – Konfigurierbarer Heartbeat mit Timer-Integration

Proxy-Tunneling

  • HTTP CONNECT – Proxy-Tunneling mit Basic-Authentifizierung
  • SOCKS4/4a – Legacy-SOCKS-Unterstützung
  • SOCKS5 – RFC 1928/1929 mit Benutzername/Passwort-Authentifizierung
  • Async-API – Nicht blockierende Proxy-Verbindung mit Zustandsmaschine

Ereignissystem

  • Plattformübergreifende Abfrage – epoll (Linux), kqueue (BSD/macOS), poll-Fallback
  • Edge-Triggered-Modus – Hochleistungs-Ereignisbenachrichtigung
  • Asynchrone I/O – io_uring (Linux 5.1+), kqueue AIO (BSD/macOS)
  • Timer – Einmalig und wiederholend mit O(log n) Min-Heap

Verbindungsverwaltung

  • Verbindungspooling – O(1)-Suche mit Hash-Tabellen, verbindungsspezifische I/O-Puffer
  • Happy Eyeballs – RFC 8305 Dual-Stack IPv4/IPv6-Verbindungsrennen
  • Automatische Wiederverbindung – Exponentielles Backoff mit Circuit-Breaker-Muster
  • Graceful Shutdown – Pool-Drain-Zustandsmaschine mit Timeout-Garantie

Sicherheitshärtung

  • SYN-Flood-Schutz – Reputationsbewertung, Drosselung, Kernel-Integration
  • Pro-IP-Verfolgung – Verbindungslimits und Ratenbegrenzung pro Client
  • Ratenbegrenzung – Token-Bucket-Algorithmus für Verbindungen und Bandbreite
  • Request-Smuggling-Verhinderung – Strenge HTTP-Analyse mit RFC-Konformität

DNS-Auflösung

  • Async-Resolver – Nicht blockierende Auflösung mit Thread-Pool und Query-Multiplexing
  • DNS-over-TLS (DoT) – RFC 7858/8310 verschlüsseltes DNS mit opportunistischem/striktem Modus
  • DNS-over-HTTPS (DoH) – RFC 8484 DNS-Abfragen über HTTPS (POST/GET-Methoden)
  • DNSSEC-Validierung – RFC 4033-4035 Vertrauenskette, NSEC/NSEC3 authentifizierte Verneinung
  • DNS-Cookies – RFC 7873 Spoofing-Schutz über EDNS0
  • Negatives Caching – RFC 2308 korrekte NXDOMAIN/NODATA-Behandlung
  • Erweiterte DNS-Fehler – RFC 8914 detaillierte Fehlercodes

Infrastruktur

  • Ausnahmebasierte Fehler – Saubere Fehlerweitergabe mit TRY/EXCEPT/FINALLY
  • Einfache API – Rückgabecodebasierte Komfortschicht für allgemeine Operationen (kein TRY/EXCEPT nötig)
  • Arena-Speicherverwaltung – Effiziente Allokation mit Überlaufschutz
  • Ringpuffer-I/O – Zero-Copy-Pufferung für Netzwerkoperationen
  • Asynchrone I/O – Plattformoptimierte asynchrone Operationen (io_uring/kqueue)
  • UTF-8-Validierung – Sicherheitsorientierte UTF-8-Verarbeitung für WebSocket-Textframes
  • Generisches Wiederholungsframework – Exponentielles Backoff mit Jitter für resiliente Operationen
  • Pro-IP-Verbindungsverfolgung – Verbindungslimits und Ratenbegrenzung pro Client-IP
  • Zero-Copy-I/O – Plattformoptimiertes sendfile() und Scatter/Gather-I/O
  • Beobachtbarkeit – Einsteckbare Protokollierung, Prometheus/StatsD/JSON-Metrikexport, Ereignisverteilung
  • Kryptografische Werkzeuge – SHA-1/256, HMAC, Base64, sicheres Zufallszahlen

Plattformanforderungen

  • POSIX-konformes System (Linux, BSD, macOS)
  • C11-Compiler mit GNU-Erweiterungen
  • POSIX-Threads (pthread) für threadsichere Operationen
  • IPv6-Unterstützung im Kernel (für Dual-Stack-Sockets)
  • Nicht auf Windows portierbar ohne Winsock-Anpassungsschicht

Plattformspezifische Funktionen

TLS/DTLS-Anforderungen

  • OpenSSL 1.1.1+ oder LibreSSL mit TLS 1.3-Unterstützung
  • Standardmäßig nur TLS 1.3 (konfigurierbar)
  • DTLS 1.2 mindestens für sicheres UDP

Schnellstart

Kompilieren```bash

Basic build

cmake -S . -B build cmake --build build -j

Run tests

cd build && ctest --output-on-failure

Build with TLS support (auto-detects OpenSSL/LibreSSL)

cmake -S . -B build -DENABLE_TLS=ON

Build with sanitizers for debugging

cmake -S . -B build -DENABLE_SANITIZERS=ON

Build with fuzzing support (requires Clang)

cmake -S . -B build -DENABLE_FUZZING=ON -DCMAKE_C_COMPILER=clang

root@kitploit:~
### Einfacher TCP-Server```c
#include "socket/Socket.h"
#include "core/Except.h"
#include <stdio.h>

int main(void)
{
    Socket_T server = Socket_new(AF_INET, SOCK_STREAM, 0);
    
    TRY
        Socket_setreuseaddr(server);
        Socket_bind(server, NULL, 8080);
        Socket_listen(server, 128);
        printf("Server listening on port 8080...\n");
        
        while (1) {
            Socket_T client = Socket_accept(server);
            if (client) {
                char buf[1024];
                ssize_t n = Socket_recv(client, buf, sizeof(buf) - 1);
                if (n > 0) {
                    buf[n] = '\0';
                    Socket_sendall(client, buf, n);
                }
                Socket_free(&client);
            }
        }
    EXCEPT(Socket_Failed)
        fprintf(stderr, "Error: %s\n", Socket_GetLastError());
    END_TRY;
    
    Socket_free(&server);
    return 0;
}

Einfacher TCP-Client```c

#include "socket/Socket.h" #include "core/Except.h" #include <stdio.h> #include <string.h>

int main(void) { Socket_T client = Socket_new(AF_INET, SOCK_STREAM, 0);

root@kitploit:~
TRY
    Socket_connect(client, "127.0.0.1", 8080);
    printf("Connected to server\n");
    
    const char *msg = "Hello, Server!";
    Socket_sendall(client, msg, strlen(msg));
    
    char buf[1024];
    ssize_t n = Socket_recvall(client, buf, strlen(msg));
    buf[n] = '\0';
    printf("Received: %s\n", buf);
EXCEPT(Socket_Failed)
    fprintf(stderr, "Error: %s\n", Socket_GetLastError());
EXCEPT(Socket_Closed)
    fprintf(stderr, "Connection closed\n");
END_TRY;

Socket_free(&client);
return 0;

}

root@kitploit:~
### Praktische Funktionen (Ein-Klick-Einrichtung)

Für häufige Anwendungsfälle vereinfachen praktische Funktionen die Socket-Einrichtung:```c
#include "socket/Socket.h"
#include "socket/SocketDgram.h"

/* TCP Server - one call creates listening socket */
Socket_T server = Socket_listen_tcp("0.0.0.0", 8080, 128);
while (running) {
    Socket_T client = Socket_accept_timeout(server, 1000);  // 1s timeout
    if (client) handle_client(client);
}
Socket_free(&server);

/* TCP Client with timeout - one call connects */
Socket_T client = Socket_connect_tcp("api.example.com", 443, 5000);  // 5s timeout
Socket_sendall(client, request, len);
Socket_free(&client);

/* UDP Server - one call binds */
SocketDgram_T udp = SocketDgram_bind_udp("0.0.0.0", 5353);
SocketDgram_recvfrom(udp, buf, sizeof(buf), sender_ip, sizeof(sender_ip), &sender_port);
SocketDgram_free(&udp);

/* Unix Domain Server */
Socket_T unix_srv = Socket_listen_unix("/var/run/app.sock", 128);
Socket_free(&unix_srv);

/* Unix Domain Client with timeout */
Socket_T unix_cli = Socket_new(AF_UNIX, SOCK_STREAM, 0);
Socket_connect_unix_timeout(unix_cli, "/var/run/app.sock", 5000);
Socket_free(&unix_cli);

/* Non-blocking connect (for event loops) */
Socket_T sock = Socket_new(AF_INET, SOCK_STREAM, 0);
int status = Socket_connect_nonblocking(sock, "192.168.1.1", 8080);
if (status == 1) {
    /* In progress - poll for POLL_WRITE then check Socket_isconnected() */
}

Einfache API (kein TRY/EXCEPT erforderlich)

Für Benutzer, die eine auf Rückgabecodes basierende Fehlerbehandlung bevorzugen, bietet die Simple API eine Komfortschicht, die die ausnahmebasierten Interna kapselt:```c #include "simple/SocketSimple.h"

/* TCP Client - returns NULL on error */ SocketSimple_Socket_T sock = Socket_simple_connect("example.com", 80); if (!sock) { fprintf(stderr, "Error: %s\n", Socket_simple_error()); return 1; } Socket_simple_send(sock, "GET / HTTP/1.0\r\n\r\n", 18); char buf[4096]; ssize_t n = Socket_simple_recv(sock, buf, sizeof(buf)); Socket_simple_close(&sock);

/* TLS Client - one-liner with cert verification */ SocketSimple_Socket_T tls = Socket_simple_connect_tls("api.example.com", 443); if (tls) { Socket_simple_send(tls, request, len); Socket_simple_close(&tls); }

/* HTTP GET - returns 0 on success */ SocketSimple_HTTPResponse resp; if (Socket_simple_http_get("https://api.example.com/data", &resp) == 0) { printf("Status: %d, Body: %.*s\n", resp.status_code, (int)resp.body_len, resp.body); Socket_simple_http_response_free(&resp); }

/* WebSocket - handles ws:// and wss:// */ SocketSimple_WS_T ws = Socket_simple_ws_connect("wss://echo.example.com/ws"); if (ws) { Socket_simple_ws_send_text(ws, "Hello!", 6); SocketSimple_WSMessage msg; if (Socket_simple_ws_recv(ws, &msg) == 0) { printf("Received: %.*s\n", (int)msg.len, (char *)msg.data); Socket_simple_ws_message_free(&msg); } Socket_simple_ws_close(ws, 1000, "Bye"); Socket_simple_ws_free(&ws); }

root@kitploit:~
Siehe [docs/simple.md](https://github.com/7etsuo/tetsuo-pulse/blob/HEAD/docs/simple.md) für die vollständige API-Dokumentation.

## Nutzungsmuster

### Fehlerbehandlung

Alle Socket-Operationen verwenden eine ausnahmebasierte Fehlerbehandlung:```c
TRY
    Socket_connect(socket, "example.com", 80);
    Socket_sendall(socket, data, len);
EXCEPT(Socket_Failed)
    if (Socket_error_is_retryable(Socket_geterrno()))
        /* Schedule retry with backoff */
    else
        fprintf(stderr, "Fatal error: %s\n", Socket_Failed.reason);
EXCEPT(Socket_Closed)
    fprintf(stderr, "Connection closed\n");
FINALLY
    Socket_free(&socket);
END_TRY;

Nicht blockierendes I/O mit Event-Polling```c

#include "socket/Socket.h" #include "poll/SocketPoll.h"

Socket_T server = Socket_new(AF_INET, SOCK_STREAM, 0); Socket_setreuseaddr(server); Socket_bind(server, NULL, 8080); Socket_listen(server, 128); Socket_setnonblocking(server);

SocketPoll_T poll = SocketPoll_new(1000); SocketPoll_add(poll, server, POLL_READ, NULL);

while (1) { SocketEvent_T *events; int n = SocketPoll_wait(poll, &events, 1000);

root@kitploit:~
for (int i = 0; i < n; i++) {
    if (events[i].socket == server) {
        Socket_T client = Socket_accept(server);
        if (client) {
            Socket_setnonblocking(client);
            SocketPoll_add(poll, client, POLL_READ, client);
        }
    } else {
        Socket_T client = events[i].socket;
        char buf[1024];
        ssize_t bytes = Socket_recv(client, buf, sizeof(buf));
        if (bytes > 0) {
            Socket_sendall(client, buf, bytes);
        } else {
            SocketPoll_del(poll, client);
            Socket_free(&client);
        }
    }
}

}

SocketPoll_free(&poll); Socket_free(&server);

root@kitploit:~
### HTTP Client```c
#include "http/SocketHTTPClient.h"

/* Simple GET request */
SocketHTTPClient_T client = SocketHTTPClient_new(NULL);
SocketHTTPClient_Response response = {0};

if (SocketHTTPClient_get(client, "https://example.com/api", &response) == 0) {
    printf("Status: %d\n", response.status_code);
    printf("Body: %.*s\n", (int)response.body_len, (char *)response.body);
}
SocketHTTPClient_Response_free(&response);

/* Request builder pattern */
SocketHTTPClient_Request_T req = SocketHTTPClient_Request_new(
    client, HTTP_METHOD_POST, "https://api.example.com/data");
SocketHTTPClient_Request_header(req, "Content-Type", "application/json");
SocketHTTPClient_Request_body(req, "{\"key\": \"value\"}", 16);
SocketHTTPClient_Request_timeout(req, 30000);

if (SocketHTTPClient_Request_execute(req, &response) == 0) {
    printf("POST Status: %d\n", response.status_code);
}
SocketHTTPClient_Request_free(&req);
SocketHTTPClient_Response_free(&response);

/* Cookie jar */
SocketHTTPClient_CookieJar_T jar = SocketHTTPClient_CookieJar_new();
SocketHTTPClient_set_cookie_jar(client, jar);

SocketHTTPClient_free(&client);

HTTP-Client-Komfortfunktionen```c

#include "http/SocketHTTPClient.h"

SocketHTTPClient_T client = SocketHTTPClient_new(NULL);

/* Download file from URL */ int ret = SocketHTTPClient_download(client, "https://example.com/file.zip", "/tmp/file.zip"); if (ret == 0) { printf("Download complete\n"); } else if (ret == -1) { printf("HTTP error\n"); } else { printf("File error: %s\n", strerror(errno)); }

/* Upload file to URL */ int status = SocketHTTPClient_upload(client, "https://storage.example.com/files/upload.dat", "/path/to/local/file.dat"); if (status >= 200 && status < 300) { printf("Upload successful (HTTP %d)\n", status); }

/* JSON API calls */ char *json_response = NULL; size_t json_len;

/* GET JSON */ status = SocketHTTPClient_json_get(client, "https://api.example.com/users/123", &json_response, &json_len); if (status == 200 && json_response) { printf("User data: %s\n", json_response); free(json_response); }

/* POST JSON */ const char *request_body = "{"name": "John", "email": "[email protected]"}"; status = SocketHTTPClient_json_post(client, "https://api.example.com/users", request_body, &json_response, &json_len); if (status == 201 && json_response) { printf("Created: %s\n", json_response); free(json_response); }

SocketHTTPClient_free(&client);

root@kitploit:~
### HTTP Server

Für Details zur HTTP/2-Negotiation (ALPN vs h2c vs prior-knowledge), Stream-Lebenszyklus,
Trailern, GOAWAY/Drain und RFC 8441-Status siehe `docs/HTTP2-SERVER.md`.```c
#include "http/SocketHTTPServer.h"
#include "http/SocketHTTP.h"
#include <string.h>

static void
handle_request (SocketHTTPServer_Request_T req, void *userdata)
{
    (void)userdata;

    if (SocketHTTPServer_Request_method (req) == HTTP_METHOD_GET
        && strcmp (SocketHTTPServer_Request_path (req), "/") == 0)
      {
        SocketHTTPServer_Request_status (req, 200);
        SocketHTTPServer_Request_header (req, "content-type", "text/html");
        SocketHTTPServer_Request_body_string (req, "<h1>Hello World</h1>");
        SocketHTTPServer_Request_finish (req);
        return;
      }

    SocketHTTPServer_Request_status (req, 404);
    SocketHTTPServer_Request_body_string (req, "Not Found");
    SocketHTTPServer_Request_finish (req);
}

int
main (void)
{
    SocketHTTPServer_Config config;
    SocketHTTPServer_T server;

    SocketHTTPServer_config_defaults (&config);
    config.port = 8080;
    config.max_version = HTTP_VERSION_2;   /* Allow HTTP/2 (default) */
    config.enable_h2c_upgrade = 0;         /* h2c is opt-in */

    server = SocketHTTPServer_new (&config);
    SocketHTTPServer_set_handler (server, handle_request, NULL);
    SocketHTTPServer_start (server);

    /* Event loop */
    for (;;)
      SocketHTTPServer_process (server, 1000);
}

HTTP/2 Stream-Verwaltung```c

#include "http/SocketHTTP2.h"

/* Check connection health with PING */ int rtt = SocketHTTP2_Conn_ping_wait(conn, 5000); if (rtt >= 0) { printf("Connection alive, RTT: %d ms\n", rtt); } else { printf("Connection dead or timeout\n"); }

/* Monitor concurrent streams */ uint32_t active = SocketHTTP2_Conn_get_concurrent_streams(conn); printf("Active streams: %u\n", active);

/* Limit concurrent streams (sends SETTINGS frame) */ SocketHTTP2_Conn_set_max_concurrent(conn, 50);

/* Check peer's stream limit */ uint32_t peer_max = SocketHTTP2_Conn_get_peer_setting(conn, SETTINGS_IDX_MAX_CONCURRENT_STREAMS); printf("Peer allows %u concurrent streams\n", peer_max);

root@kitploit:~
### WebSocket-Client```c
#include "socket/SocketWS.h"

/* One-liner WebSocket connection (new convenience API) */
SocketWS_T ws = SocketWS_connect("wss://echo.websocket.org", NULL);
if (ws) {
    /* Send and receive JSON messages */
    SocketWS_send_json(ws, "{\"type\": \"hello\", \"data\": \"world\"}");
    
    char *json = NULL;
    size_t len;
    if (SocketWS_recv_json(ws, &json, &len) == WS_OK) {
        printf("Received: %s\n", json);
        free(json);
    }
    
    /* Check ping latency */
    SocketWS_ping(ws, "test", 4);
    SocketWS_process(ws, POLLIN);  /* Wait for pong */
    int64_t rtt = SocketWS_get_ping_latency(ws);
    printf("Latency: %lld ms\n", (long long)rtt);
    
    SocketWS_close(ws, WS_CLOSE_NORMAL, "Goodbye", 7);
    SocketWS_free(&ws);
}

/* Traditional multi-step connection */
Socket_T sock = Socket_new(AF_INET, SOCK_STREAM, 0);
Socket_connect(sock, "echo.websocket.org", 80);

SocketWS_Config ws_config = SOCKETWS_CONFIG_DEFAULTS;
SocketWS_T ws2 = SocketWS_client_new(sock, "echo.websocket.org", "/", &ws_config);

/* Enable compression before handshake */
SocketWS_CompressionOptions comp_opts;
SocketWS_compression_options_defaults(&comp_opts);
comp_opts.level = 9;  /* Maximum compression */
SocketWS_enable_compression(ws2, &comp_opts);

/* Perform handshake */
TRY
    SocketWS_handshake(ws2);
    
    /* Send text message */
    SocketWS_send_text(ws2, "Hello, WebSocket!", 17);
    
    /* Graceful close */
    SocketWS_close(ws2, WS_CLOSE_NORMAL, "Goodbye", 7);
EXCEPT(SocketWS_Failed)
    fprintf(stderr, "WebSocket error: %s\n", SocketWS_Failed.reason);
END_TRY;

SocketWS_free(&ws2);
Socket_free(&sock);

QUIC Client```c

#include "quic/SocketQUICConnection.h" #include "quic/SocketQUICStream.h" #include "quic/SocketQUICHandshake.h"

/* Create QUIC connection */ Arena_T arena = Arena_new(); SocketQUICConnection_T conn = SocketQUICConnection_new(arena, QUIC_CONN_ROLE_CLIENT);

/* Configure connection parameters */ SocketQUICConnection_set_initial_dcid(conn, dcid, dcid_len); SocketQUICConnection_set_local_addr(conn, local_addr, local_port); SocketQUICConnection_set_peer_addr(conn, peer_addr, peer_port);

/* Create bidirectional stream */ SocketQUICStream_T stream = SocketQUICStream_new(arena, 0, QUIC_STREAM_BIDI); SocketQUICStream_write(stream, data, len);

/* Process handshake */ SocketQUICHandshake_T hs = SocketQUICHandshake_new(arena, QUIC_HANDSHAKE_CLIENT); while (SocketQUICHandshake_state(hs) != QUIC_HS_STATE_COMPLETE) { SocketQUICHandshake_process(hs); }

/* Read stream data */ uint8_t buf[4096]; size_t bytes_read = SocketQUICStream_read(stream, buf, sizeof(buf));

/* Clean up */ SocketQUICStream_free(&stream); SocketQUICConnection_free(&conn); Arena_dispose(&arena);

root@kitploit:~
### Proxy-Tunneling```c
#include "socket/SocketProxy.h"

/* SOCKS5 proxy configuration */
SocketProxy_Config proxy = {0};
proxy.type = SOCKET_PROXY_SOCKS5;
proxy.host = "proxy.example.com";
proxy.port = 1080;
proxy.username = "user";
proxy.password = "secret";

Socket_T sock = Socket_new(AF_INET, SOCK_STREAM, 0);

/* Connect through proxy (synchronous) */
SocketProxy_Result result = SocketProxy_connect(sock, &proxy, "target.example.com", 443);
if (result == PROXY_OK) {
    /* Socket is now tunneled - proceed with TLS handshake if needed */
    SocketTLS_enable(sock, tls_ctx);
    SocketTLS_handshake_loop(sock, 10000);
}

/* HTTP CONNECT proxy */
SocketProxy_Config http_proxy = {0};
http_proxy.type = SOCKET_PROXY_HTTP;
http_proxy.host = "httpproxy.example.com";
http_proxy.port = 8080;
http_proxy.username = "user";
http_proxy.password = "pass";

/* Asynchronous proxy connection */
SocketProxy_Conn_T conn = SocketProxy_Conn_new(sock, &http_proxy, "target.com", 443);
while (!SocketProxy_Conn_poll(conn)) {
    int timeout = SocketProxy_Conn_next_timeout_ms(conn);
    SocketPoll_wait(poll, &events, timeout);
    SocketProxy_Conn_process(conn);
}
result = SocketProxy_Conn_result(conn);
SocketProxy_Conn_free(&conn);

DTLS (Sicheres UDP)```c

#include "tls/SocketDTLS.h" #include "tls/SocketDTLSContext.h" #include "socket/SocketDgram.h"

/* DTLS Client */ SocketDgram_T sock = SocketDgram_new(AF_INET, 0); SocketDgram_connect(sock, "server.example.com", 5684);

SocketDTLSContext_T ctx = SocketDTLSContext_new_client("ca-bundle.crt"); SocketDTLS_enable(sock, ctx); SocketDTLS_set_hostname(sock, "server.example.com");

DTLSHandshakeState state = SocketDTLS_handshake_loop(sock, 5000); if (state == DTLS_HANDSHAKE_COMPLETE) { /* Send encrypted datagram */ SocketDTLS_send(sock, "Hello DTLS", 10);

root@kitploit:~
char buf[1024];
ssize_t n = SocketDTLS_recv(sock, buf, sizeof(buf));

}

SocketDTLS_shutdown(sock); SocketDgram_free(&sock); SocketDTLSContext_free(&ctx);

/* DTLS Server with cookie exchange */ SocketDgram_T server = SocketDgram_new(AF_INET, 0); SocketDgram_bind(server, "0.0.0.0", 5684);

SocketDTLSContext_T srv_ctx = SocketDTLSContext_new_server("cert.pem", "key.pem", NULL); SocketDTLSContext_enable_cookie_exchange(srv_ctx); /* DoS protection */ SocketDTLS_enable(server, srv_ctx);

/* Handle incoming connections with SocketDTLS_listen() */

root@kitploit:~
### UDP-Server```c
#include "socket/SocketDgram.h"

SocketDgram_T server = SocketDgram_new(AF_INET, 0);
SocketDgram_bind(server, NULL, 5000);

char buffer[65536];
char sender_host[46];
int sender_port;

while (1) {
    ssize_t n = SocketDgram_recvfrom(server, buffer, sizeof(buffer),
                                     sender_host, sizeof(sender_host),
                                     &sender_port);
    if (n > 0) {
        /* Echo back to sender */
        SocketDgram_sendto(server, buffer, n, sender_host, sender_port);
    }
}

SocketDgram_free(&server);

Verbindungspooling mit Ratenbegrenzung```c

#include "pool/SocketPool.h" #include "core/Arena.h"

Arena_T arena = Arena_new(); SocketPool_T pool = SocketPool_new(arena, 10000, 8192);

/* Enable rate limiting: 100 connections/sec, burst of 50 */ SocketPool_setconnrate(pool, 100, 50);

/* Limit per-IP connections */ SocketPool_setmaxperip(pool, 10);

/* Rate-limited accept with error handling / Socket_T client = SocketPool_accept_limited(pool, server); if (client) { Connection_T conn = SocketPool_add(pool, client); if (conn) { SocketBuf_T input = Connection_inbuf(conn); SocketBuf_T output = Connection_outbuf(conn); / ... use connection ... / } else { / Pool full or other error - cleanup to avoid leaks */ const char *ip = Socket_getpeeraddr(client); SocketPool_release_ip(pool, ip); Socket_free(&client); } }

/* Batch accept for high-throughput servers */ Socket_T accepted[32]; int count = SocketPool_accept_batch(pool, server, 32, accepted);

/* Clean up idle connections / SocketPool_cleanup(pool, 300); / Remove idle > 300 seconds */

SocketPool_free(&pool); Arena_dispose(&arena);

root@kitploit:~
### Verbindungspool-Statistiken & Filterung```c
#include "pool/SocketPool.h"

/* Get pool statistics */
SocketPool_Stats stats;
SocketPool_get_stats(pool, &stats);
printf("Active: %zu, Idle: %zu, Reuse rate: %.1f%%\n",
       stats.current_active, stats.current_idle, stats.reuse_rate * 100.0);

/* Convenience stat functions */
size_t active = SocketPool_get_active_count(pool);
size_t idle = SocketPool_get_idle_count(pool);
double hit_rate = SocketPool_get_hit_rate(pool);

/* Find connections matching criteria */
int is_from_subnet(Connection_T conn, void *data) {
    const char *subnet = (const char *)data;
    return strncmp(Socket_getpeeraddr(Connection_socket(conn)), subnet, 7) == 0;
}

/* Find first matching connection */
Connection_T conn = SocketPool_find(pool, is_from_subnet, "192.168");

/* Get all matching connections */
Connection_T matches[100];
size_t count = SocketPool_filter(pool, is_from_subnet, "192.168", matches, 100);
for (size_t i = 0; i < count; i++) {
    /* Process matching connections */
}

/* Register idle callback */
void on_idle(Connection_T conn, void *data) {
    printf("Connection went idle: %s\n",
           Socket_getpeeraddr(Connection_socket(conn)));
}
SocketPool_set_idle_callback(pool, on_idle, NULL);

/* Shrink pool to release unused memory */
size_t released = SocketPool_shrink(pool);
printf("Released %zu unused slots\n", released);

/* Reset statistics for new measurement window */
SocketPool_reset_stats(pool);

Ringpuffer-Operationen```c

#include "socket/SocketBuf.h"

Arena_T arena = Arena_new(); SocketBuf_T buf = SocketBuf_new(arena, 4096);

/* Basic read/write */ SocketBuf_write(buf, "Hello, World!\n", 14); printf("Available: %zu bytes\n", SocketBuf_available(buf));

/* Search for patterns (useful for protocol parsing) / ssize_t pos = SocketBuf_find(buf, "\n", 1); / Find newline */ if (pos >= 0) { printf("Newline at offset %zd\n", pos); }

/* Read line-by-line / char line[256]; ssize_t len; while ((len = SocketBuf_readline(buf, line, sizeof(line))) > 0) { printf("Line: %s", line); / Includes '\n' */ }

/* Ensure space for large write / if (SocketBuf_ensure(buf, 8192)) { / Guaranteed 8KB write space */ SocketBuf_write(buf, large_data, 8192); }

/* Compact buffer for maximum contiguous space */ SocketBuf_compact(buf); size_t contiguous; void ptr = SocketBuf_writeptr(buf, &contiguous); / contiguous now equals SocketBuf_space(buf) */

/* Scatter-gather I/O / struct header hdr = {...}; char body[1024] = "..."; struct iovec iov[2] = { {.iov_base = &hdr, .iov_len = sizeof(hdr)}, {.iov_base = body, .iov_len = strlen(body)} }; SocketBuf_writev(buf, iov, 2); / Gather write */

struct header recv_hdr; char recv_body[1024]; struct iovec recv_iov[2] = { {.iov_base = &recv_hdr, .iov_len = sizeof(recv_hdr)}, {.iov_base = recv_body, .iov_len = sizeof(recv_body)} }; SocketBuf_readv(buf, recv_iov, 2); /* Scatter read */

/* Secure clear for sensitive data */ SocketBuf_secureclear(buf);

SocketBuf_release(&buf); Arena_dispose(&arena);

root@kitploit:~
### SYN Flood Schutz```c
#include "core/SocketSYNProtect.h"

SocketSYNProtect_Config config = SYNPROTECT_CONFIG_DEFAULTS;
config.max_connections_per_ip = 10;
config.connection_rate_limit = 100;
config.challenge_threshold = 0.5;  /* Reputation score threshold */
config.block_threshold = 0.2;

SocketSYNProtect_T protect = SocketSYNProtect_new(NULL, &config);

/* On each incoming connection */
struct sockaddr_in client_addr;
socklen_t addr_len = sizeof(client_addr);
int client_fd = accept(server_fd, (struct sockaddr *)&client_addr, &addr_len);

SYNAction action = SocketSYNProtect_check(protect, &client_addr, addr_len);

switch (action) {
case SYN_ACTION_ALLOW:
    /* Accept connection normally */
    break;
case SYN_ACTION_THROTTLE:
    /* Accept but add delay */
    usleep(100000);
    break;
case SYN_ACTION_CHALLENGE:
    /* Send SYN cookie / challenge */
    break;
case SYN_ACTION_BLOCK:
    /* Reject connection */
    close(client_fd);
    break;
}

/* Report connection result for reputation update */
SocketSYNProtect_report(protect, &client_addr, addr_len, success);

/* Get statistics */
SocketSYNProtect_Stats stats;
SocketSYNProtect_stats(protect, &stats);

SocketSYNProtect_free(&protect);

Geordnetes Herunterfahren```c

#include "pool/SocketPool.h"

/* Non-blocking drain for event loops / SocketPool_drain(pool, 30000); / Start 30s drain / while (SocketPool_drain_poll(pool) > 0) { SocketPoll_wait(poll, &events, SocketPool_drain_remaining_ms(pool)); / Process remaining events, connections closing naturally */ } SocketPool_free(&pool);

/* Blocking drain (convenience) / int result = SocketPool_drain_wait(pool, 30000); if (result < 0) { / Timeout - connections were force-closed */ }

/* Health check for load balancers / SocketPool_Health health = SocketPool_health(pool); if (health == POOL_HEALTH_DRAINING) { / Return 503 to load balancer */ }

root@kitploit:~
### Happy Eyeballs Connection (RFC 8305)```c
#include "socket/SocketHappyEyeballs.h"

/* Synchronous - races IPv6 and IPv4 for fastest connection */
Socket_T sock = SocketHappyEyeballs_connect("example.com", 443, NULL);
Socket_sendall(sock, "GET / HTTP/1.1\r\n\r\n", 18);
Socket_free(&sock);

/* Asynchronous - for event-driven applications */
SocketHE_Config_T config;
SocketHappyEyeballs_config_defaults(&config);
config.first_attempt_delay_ms = 250;  /* RFC 8305 default */
config.total_timeout_ms = 30000;

SocketHE_T he = SocketHappyEyeballs_start(dns, poll, "example.com", 443, &config);
while (!SocketHappyEyeballs_poll(he)) {
    int timeout = SocketHappyEyeballs_next_timeout_ms(he);
    SocketPoll_wait(poll, &events, timeout);
    SocketHappyEyeballs_process(he);
}
Socket_T result = SocketHappyEyeballs_result(he);
SocketHappyEyeballs_free(&he);

Automatische Wiederverbindung mit Circuit Breaker```c

#include "socket/SocketReconnect.h"

/* Configure reconnection policy */ SocketReconnect_Policy_T policy; SocketReconnect_policy_defaults(&policy); policy.initial_delay_ms = 100; policy.max_delay_ms = 30000; policy.multiplier = 2.0; policy.jitter = 0.25; policy.max_attempts = 10; policy.circuit_failure_threshold = 5; policy.circuit_reset_timeout_ms = 60000;

void on_state_change(SocketReconnect_T conn, SocketReconnect_State old, SocketReconnect_State new, void *data) { printf("State: %s -> %s\n", SocketReconnect_state_name(old), SocketReconnect_state_name(new)); }

SocketReconnect_T conn = SocketReconnect_new("example.com", 443, &policy, on_state_change, NULL); SocketReconnect_connect(conn);

/* Event loop */ while (running) { int timeout = SocketReconnect_next_timeout_ms(conn); poll(&pfd, 1, timeout); SocketReconnect_process(conn); SocketReconnect_tick(conn);

root@kitploit:~
if (SocketReconnect_isconnected(conn)) {
    /* I/O with auto-reconnect on error */
    ssize_t n = SocketReconnect_send(conn, data, len);
}

}

SocketReconnect_free(&conn);

root@kitploit:~
### Allgemeines Wiederholungs-Framework```c
#include "core/SocketRetry.h"

/* Configure retry policy */
SocketRetry_Policy policy;
SocketRetry_policy_defaults(&policy);
policy.max_attempts = 5;
policy.initial_delay_ms = 100;
policy.max_delay_ms = 30000;
policy.multiplier = 2.0;
policy.jitter = 0.25;

/* Define operation to retry */
int connect_op(void *ctx, int attempt) {
    ConnectionCtx *c = ctx;
    return connect(c->fd, c->addr, c->addrlen) < 0 ? errno : 0;
}

/* Define retry decision callback */
int should_retry(int err, int attempt, void *ctx) {
    return SocketError_is_retryable_errno(err);
}

/* Execute with retries */
SocketRetry_T retry = SocketRetry_new(&policy);
int result = SocketRetry_execute(retry, connect_op, should_retry, &ctx);

/* Get statistics */
SocketRetry_Stats stats;
SocketRetry_get_stats(retry, &stats);
printf("Attempts: %d, Total delay: %lld ms\n", stats.attempts, stats.total_delay_ms);

SocketRetry_free(&retry);

Asynchrone DNS-Auflösung```c

#include "dns/SocketDNS.h" #include "poll/SocketPoll.h"

SocketDNS_T dns = SocketDNS_new(); SocketPoll_T poll = SocketPoll_new(100);

/* Configure DNS timeouts / SocketDNS_settimeout(dns, 5000); / 5 second default timeout */

/* Configure DNS cache / SocketDNS_cache_set_ttl(dns, 300); / 5 minute TTL / SocketDNS_cache_set_max_entries(dns, 1000); / Max 1000 entries / SocketDNS_prefer_ipv6(dns, 1); / Prefer IPv6 */

/* Start async resolution */ SocketDNS_Request_T req = SocketDNS_resolve(dns, "example.com", 80, NULL, NULL);

/* Per-request timeout override */ SocketDNS_request_settimeout(dns, req, 10000);

/* In event loop, check for completions */ SocketDNS_check(dns);

/* Get result */ struct addrinfo *result = SocketDNS_getresult(dns, req); if (result) { Socket_connect_with_addrinfo(socket, result); freeaddrinfo(result); } else { int error = SocketDNS_geterror(dns, req); fprintf(stderr, "DNS failed: %s\n", gai_strerror(error)); }

/* Monitor cache performance */ SocketDNS_CacheStats stats; SocketDNS_cache_stats(dns, &stats); printf("DNS cache hit rate: %.1f%% (%zu entries)\n", stats.hit_rate * 100.0, stats.current_size);

/* Clear cache when DNS records change */ SocketDNS_cache_clear(dns);

/* Remove specific entry */ SocketDNS_cache_remove(dns, "example.com");

SocketDNS_free(&dns); SocketPoll_free(&poll);

root@kitploit:~
### Asynchrone I/O (io_uring/kqueue)```c
#include "socket/SocketAsync.h"
#include "poll/SocketPoll.h"

/* Check what backend is available */
if (SocketAsync_backend_available(ASYNC_BACKEND_IO_URING)) {
    printf("io_uring available - optimal async I/O\n");
} else if (SocketAsync_backend_available(ASYNC_BACKEND_KQUEUE)) {
    printf("kqueue available - good async I/O\n");
} else {
    printf("Using poll-based fallback\n");
}

/* Set preferred backend (optional) */
SocketAsync_set_backend(ASYNC_BACKEND_IO_URING);

/* Get async context from poll */
SocketPoll_T poll = SocketPoll_new(1024);
SocketAsync_T async = SocketPoll_get_async(poll);

/* Completion callback */
void io_complete(Socket_T socket, ssize_t bytes, int err, void *ud) {
    if (err) {
        printf("Error: %s\n", strerror(err));
        return;
    }
    printf("Transferred %zd bytes\n", bytes);
}

/* Submit async send */
unsigned req_id = SocketAsync_send(async, socket, buf, len,
                                   io_complete, userdata, ASYNC_FLAG_NONE);

/* Submit async recv */
req_id = SocketAsync_recv(async, socket, recv_buf, sizeof(recv_buf),
                          io_complete, userdata, ASYNC_FLAG_ZERO_COPY);

/* Batch submission for efficiency */
SocketAsync_Op ops[3] = {
    {sock1, 1, send_buf, NULL, len1, io_complete, ud1, ASYNC_FLAG_NONE, 0},
    {sock2, 0, NULL, recv_buf, len2, io_complete, ud2, ASYNC_FLAG_NONE, 0},
    {sock3, 1, send_buf2, NULL, len3, io_complete, ud3, ASYNC_FLAG_URGENT, 0}
};
int submitted = SocketAsync_submit_batch(async, ops, 3);
printf("Submitted %d operations\n", submitted);

/* Cancel specific operation */
SocketAsync_cancel(async, req_id);

/* Cancel all pending (during shutdown) */
int cancelled = SocketAsync_cancel_all(async);
printf("Cancelled %d pending ops\n", cancelled);

/* Check backend in use */
printf("Backend: %s, available: %s\n",
       SocketAsync_backend_name(async),
       SocketAsync_is_available(async) ? "yes" : "fallback");

/* Completions auto-processed in SocketPoll_wait() */
SocketEvent_T *events;
int n = SocketPoll_wait(poll, &events, 100);

SocketPoll_free(&poll);

Bandbreitenbegrenzung```c

#include "socket/Socket.h"

Socket_T socket = Socket_new(AF_INET, SOCK_STREAM, 0); Socket_connect(socket, "example.com", 80);

/* Enable bandwidth limiting: 1 MB/sec */ Socket_setbandwidth(socket, 1024 * 1024);

/* Rate-limited send / ssize_t n = Socket_send_limited(socket, data, len); if (n == 0) { / Rate limited - wait before retry / int64_t wait_ms = Socket_bandwidth_wait_ms(socket, len); / Use wait_ms as poll timeout */ }

/* Query current limit */ size_t limit = Socket_getbandwidth(socket);

Socket_free(&socket);

root@kitploit:~
### Verbindungsstatus & Test```c
#include "socket/Socket.h"

Socket_T sock = Socket_new(AF_INET, SOCK_STREAM, 0);
Socket_connect(sock, "example.com", 80);

/* Quick health check (non-blocking) */
if (!Socket_probe(sock, 0)) {
    printf("Connection appears dead\n");
}

/* Health check with timeout (waits up to 100ms for response) */
if (!Socket_probe(sock, 100)) {
    printf("Connection lost, reconnecting...\n");
}

/* Check for pending socket errors (after non-blocking connect) */
int error = Socket_get_error(sock);
if (error != 0) {
    printf("Socket error: %s\n", strerror(error));
}

/* Check read/write readiness without blocking */
if (Socket_is_readable(sock) > 0) {
    char buf[1024];
    ssize_t n = Socket_recv(sock, buf, sizeof(buf));
}

if (Socket_is_writable(sock) > 0) {
    Socket_send(sock, "GET / HTTP/1.1\r\n\r\n", 18);
}

#ifdef __linux__
/* Get TCP stack statistics (Linux only) */
SocketTCPInfo info;
if (Socket_get_tcp_info(sock, &info) == 0) {
    printf("RTT: %.2f ms\n", info.rtt_us / 1000.0);
    printf("Congestion window: %u segments\n", info.snd_cwnd);
    printf("Retransmissions: %u\n", info.total_retrans);
    if (info.delivery_rate > 0) {
        printf("Delivery rate: %.2f Mbps\n", info.delivery_rate * 8.0 / 1e6);
    }
}
#endif

/* Simple RTT query (cross-platform, returns -1 if unavailable) */
int32_t rtt = Socket_get_rtt(sock);
if (rtt >= 0) {
    printf("RTT: %.2f ms\n", rtt / 1000.0);
}

/* Congestion window query (Linux only) */
int32_t cwnd = Socket_get_cwnd(sock);
if (cwnd >= 0) {
    printf("CWND: %d segments\n", cwnd);
}

Socket_free(&sock);

I/O mit Timeouts```c

#include "socket/Socket.h"

Socket_T sock = Socket_connect_tcp("example.com", 80, 5000);

/* Send all data with timeout (returns bytes actually sent) */ ssize_t sent = Socket_sendall_timeout(sock, request, len, 10000); if (sent < (ssize_t)len) { printf("Only sent %zd bytes before timeout\n", sent); }

/* Receive with timeout (returns bytes received) */ char response[4096]; ssize_t n = Socket_recvall_timeout(sock, response, sizeof(response), 5000); if (n > 0) { printf("Received %zd bytes\n", n); }

/* Scatter/gather I/O with timeout */ struct iovec iov[2] = { {.iov_base = header, .iov_len = header_len}, {.iov_base = body, .iov_len = body_len} }; ssize_t sent_v = Socket_sendv_timeout(sock, iov, 2, 5000);

Socket_free(&sock);

root@kitploit:~
### Erweiterte I/O-Operationen```c
#include "socket/Socket.h"

/* Peek at data without consuming */
char peek_buf[16];
ssize_t peeked = Socket_peek(sock, peek_buf, sizeof(peek_buf));
if (peeked > 0) {
    printf("Peeked %zd bytes: protocol=%d\n", peeked, peek_buf[0]);
}

/* TCP cork for efficient message assembly */
Socket_cork(sock, 1);  /* Enable corking */
Socket_send(sock, headers, header_len);
Socket_send(sock, body, body_len);
Socket_cork(sock, 0);  /* Disable cork, flush all data */

#ifdef __linux__
/* Zero-copy socket-to-socket transfer (Linux only) */
ssize_t spliced = Socket_splice(client, upstream, 65536);
if (spliced > 0) {
    printf("Spliced %zd bytes\n", spliced);
} else if (spliced == 0) {
    /* Would block - poll for readiness */
} else {
    /* Not supported on this platform */
    char buf[4096];
    while ((n = Socket_recv(client, buf, sizeof(buf))) > 0) {
        Socket_sendall(upstream, buf, n);
    }
}
#endif

Socket-Duplizierung```c

#include "socket/Socket.h"

Socket_T socket = Socket_connect_tcp("example.com", 80, 5000);

/* Duplicate socket for separate reader/writer threads */ Socket_T reader = socket; Socket_T writer = Socket_dup(socket);

/* Now can be used in separate threads safely / / reader thread: Socket_recv(reader, ...) / / writer thread: Socket_send(writer, ...) */

/* Duplicate to specific fd (useful for exec) / Socket_T sock_fd3 = Socket_dup2(socket, 3); if (fork() == 0) { / Child process can access socket on fd 3 */ execl("/usr/bin/handler", "handler", NULL); }

Socket_free(&writer); Socket_free(&reader); Socket_free(&sock_fd3);

root@kitploit:~
### Timer```c
#include "poll/SocketPoll.h"
#include "core/SocketTimer.h"

SocketPoll_T poll = SocketPoll_new(100);

/* Check which backend is in use */
printf("Backend: %s\n", SocketPoll_get_backend_name(poll));
// Output: "epoll" (Linux), "kqueue" (macOS/BSD), or "poll" (fallback)

void timer_callback(void *userdata) {
    printf("Timer fired!\n");
}

/* One-shot timer (fires once after 5 seconds) */
SocketTimer_T timer = SocketTimer_add(poll, 5000, timer_callback, NULL);

/* Repeating timer (fires every 1 second) */
SocketTimer_T heartbeat = SocketTimer_add_repeating(poll, 1000, timer_callback, NULL);

/* Check remaining time */
int64_t remaining = SocketTimer_remaining(poll, timer);

/* Reschedule timer with new delay (extends/shortens timeout) */
SocketTimer_reschedule(poll, timer, 10000);  /* Now fires in 10 seconds */

/* Pause and resume timers */
SocketTimer_pause(poll, heartbeat);   /* Stops firing, preserves remaining time */
/* ... do something ... */
SocketTimer_resume(poll, heartbeat);  /* Continues from where it paused */

/* Cancel timer */
SocketTimer_cancel(poll, heartbeat);

/* Modify events for registered sockets */
Socket_T sock = /* ... */;
SocketPoll_add(poll, sock, POLL_READ, NULL);
SocketPoll_modify_events(poll, sock, POLL_WRITE, 0);  /* Add write monitoring */
SocketPoll_modify_events(poll, sock, 0, POLL_WRITE);  /* Remove write monitoring */

/* List registered sockets */
Socket_T sockets[100];
int count = SocketPoll_get_registered_sockets(poll, sockets, 100);
printf("Monitoring %d sockets\n", count);

/* Timers fire automatically during SocketPoll_wait() */
SocketEvent_T *events;
int n = SocketPoll_wait(poll, &events, -1);

SocketPoll_free(&poll);

Token-Bucket-Ratenbegrenzung```c

#include "core/SocketRateLimit.h"

/* Create rate limiter: 100 tokens/sec, burst capacity of 50 */ SocketRateLimit_T limiter = SocketRateLimit_new(NULL, 100, 50);

/* Try to acquire tokens (non-blocking) / if (SocketRateLimit_try_acquire(limiter, 1)) { / Allowed - proceed / handle_request(); } else { / Rate limited - calculate wait time / int64_t wait_ms = SocketRateLimit_wait_time_ms(limiter, 1); if (wait_ms > 0) { / Wait or reject */ } }

/* Query state */ size_t available = SocketRateLimit_available(limiter); size_t rate = SocketRateLimit_get_rate(limiter);

/* Reconfigure at runtime */ SocketRateLimit_configure(limiter, 200, 100);

SocketRateLimit_free(&limiter);

root@kitploit:~
### TLS/SSL Sichere Kommunikation```c
#include "tls/SocketTLS.h"
#include "tls/SocketTLSContext.h"

/* Create client TLS context */
SocketTLSContext_T ctx = SocketTLSContext_new_client("/etc/ssl/certs/ca-certificates.crt");

/* Configure ALPN protocols */
const char *protos[] = {"h2", "http/1.1"};
SocketTLSContext_set_alpn_protos(ctx, protos, 2);

/* Enable session caching for performance */
SocketTLSContext_enable_session_cache(ctx, 1000, 300);

/* Create and connect socket */
Socket_T socket = Socket_new(AF_INET, SOCK_STREAM, 0);
Socket_connect(socket, "example.com", 443);

/* Enable TLS */
SocketTLS_enable(socket, ctx);
SocketTLS_set_hostname(socket, "example.com");  /* SNI + verification */

/* Perform handshake (with timeout) */
TLSHandshakeState state = SocketTLS_handshake_loop(socket, 10000);
if (state != TLS_HANDSHAKE_COMPLETE) {
    fprintf(stderr, "Handshake failed\n");
}

/* Check negotiated protocol */
const char *alpn = SocketTLS_get_alpn_selected(socket);
printf("ALPN: %s\n", alpn ? alpn : "none");
printf("Cipher: %s\n", SocketTLS_get_cipher(socket));
printf("Version: %s\n", SocketTLS_get_version(socket));

/* Encrypted I/O */
SocketTLS_send(socket, "GET / HTTP/1.1\r\n\r\n", 18);
char buf[4096];
ssize_t n = SocketTLS_recv(socket, buf, sizeof(buf));

/* Graceful shutdown */
SocketTLS_shutdown(socket);
Socket_free(&socket);
SocketTLSContext_free(&ctx);

TLS Session Resumption```c

#include "tls/SocketTLS.h"

/* Save session for later resumption */ size_t session_len = 4096; unsigned char session_data[4096];

if (SocketTLS_session_save(sock, session_data, &session_len) == 1) { /* Store session_data[:session_len] to disk/cache */ write_session_to_cache(hostname, session_data, session_len); }

/* Later: restore session for faster reconnect */ Socket_T sock2 = Socket_connect_tcp(hostname, port, 5000); SocketTLS_enable(sock2, ctx); SocketTLS_set_hostname(sock2, hostname);

/* Restore previously saved session */ unsigned char *cached_session = read_session_from_cache(hostname, &cached_len); if (cached_session) { SocketTLS_session_restore(sock2, cached_session, cached_len); free(cached_session); }

SocketTLS_handshake_auto(sock2);

/* Check if session was resumed (0-RTT or abbreviated handshake) */ if (SocketTLS_is_session_reused(sock2)) { printf("Session resumed - faster handshake!\n"); }

root@kitploit:~
### TLS-Zertifikatinformationen```c
#include "tls/SocketTLS.h"

/* Get full certificate details */
SocketTLS_CertInfo info;
if (SocketTLS_get_peer_cert_info(sock, &info) == 1) {
    printf("Subject: %s\n", info.subject);
    printf("Issuer: %s\n", info.issuer);
    printf("Version: X.509v%d\n", info.version);
    printf("Serial: %s\n", info.serial);
    printf("Fingerprint: %s\n", info.fingerprint);
    printf("Valid from: %s", ctime(&info.not_before));
    printf("Valid until: %s", ctime(&info.not_after));
}

/* Quick certificate expiry check */
time_t expiry = SocketTLS_get_cert_expiry(sock);
if (expiry != (time_t)-1) {
    time_t now = time(NULL);
    int days_left = (expiry - now) / 86400;
    if (days_left < 30) {
        printf("Warning: Certificate expires in %d days!\n", days_left);
    }
}

/* Just get subject for logging */
char subject[256];
if (SocketTLS_get_cert_subject(sock, subject, sizeof(subject)) > 0) {
    printf("Connected to: %s\n", subject);
}

TLS OCSP und Neuverhandlung```c

#include "tls/SocketTLS.h"

/* Check OCSP stapling status */ int ocsp_status = SocketTLS_get_ocsp_response_status(sock); switch (ocsp_status) { case 1: printf("Certificate verified via OCSP\n"); break; case 0: printf("WARNING: Certificate REVOKED!\n"); Socket_free(&sock); return; case -1: printf("No OCSP response (server doesn't support stapling)\n"); break; case -2: printf("OCSP response verification failed\n"); break; }

/* Disable renegotiation for security (prevents DoS attacks) */ SocketTLS_disable_renegotiation(sock);

/* Or check for pending renegotiation requests */ int reneg = SocketTLS_check_renegotiation(sock); if (reneg == 1) { printf("Renegotiation completed\n"); } else if (reneg == -1) { printf("Renegotiation rejected (disabled or TLS 1.3)\n"); }

root@kitploit:~
### TLS-Server mit SNI und Zertifikats-Pinning```c
#include "tls/SocketTLSContext.h"

/* Create server context with primary certificate */
SocketTLSContext_T ctx = SocketTLSContext_new_server(
    "server.crt", "server.key", "ca-bundle.crt");

/* Add SNI certificates for virtual hosting */
SocketTLSContext_add_certificate(ctx, "www.example.com", 
                                  "www.crt", "www.key");
SocketTLSContext_add_certificate(ctx, "api.example.com",
                                  "api.crt", "api.key");

/* Enable client certificate verification */
SocketTLSContext_set_verify_mode(ctx, TLS_VERIFY_PEER);

/* Load CRL for revocation checking */
SocketTLSContext_load_crl(ctx, "/path/to/crl.pem");

/* Enable OCSP stapling */
unsigned char ocsp_response[4096];
size_t ocsp_len = load_ocsp_response(ocsp_response, sizeof(ocsp_response));
SocketTLSContext_set_ocsp_response(ctx, ocsp_response, ocsp_len);

/* Enable session tickets */
unsigned char ticket_key[80];
generate_ticket_key(ticket_key, sizeof(ticket_key));
SocketTLSContext_enable_session_tickets(ctx, ticket_key, sizeof(ticket_key));

/* Certificate pinning (client context) */
SocketTLSContext_T client_ctx = SocketTLSContext_new_client("ca-bundle.pem");
SocketTLSContext_add_pin_hex(client_ctx, 
    "b5bb9d8014a0f9b1d61e21e796d78dccdf1352f23cd32812f4850b878ae4944c");
SocketTLSContext_set_pin_enforcement(client_ctx, 1);  /* Strict mode */

Certificate Transparency (CT)```c

#include "tls/SocketTLSContext.h"

/* Enable Certificate Transparency validation (RFC 6962) */ SocketTLSContext_T ctx = SocketTLSContext_new_client("ca-bundle.pem");

/* Strict mode - fail if no valid SCTs */ SocketTLSContext_enable_ct(ctx, CT_VALIDATION_STRICT);

/* Or permissive mode - log but continue */ SocketTLSContext_enable_ct(ctx, CT_VALIDATION_PERMISSIVE);

/* Custom CT log list (optional) */ SocketTLSContext_set_ctlog_list_file(ctx, "/path/to/ctlogs.txt");

/* Query CT status */ if (SocketTLSContext_ct_enabled(ctx)) { CTValidationMode mode = SocketTLSContext_get_ct_mode(ctx); printf("CT validation: %s\n", mode == CT_VALIDATION_STRICT ? "strict" : "permissive"); }

root@kitploit:~
### OCSP Must-Staple (RFC 7633)```c
#include "tls/SocketTLSContext.h"

/* Create client context with must-staple enforcement */
SocketTLSContext_T ctx = SocketTLSContext_new_client("ca-bundle.pem");

/* Auto-detection: respect certificate's must-staple extension */
SocketTLSContext_set_ocsp_must_staple(ctx, OCSP_MUST_STAPLE_AUTO);

/* Or always require OCSP stapling for strict security policies */
SocketTLSContext_set_ocsp_must_staple(ctx, OCSP_MUST_STAPLE_ALWAYS);

/* Query current mode */
OCSPMustStapleMode mode = SocketTLSContext_get_ocsp_must_staple(ctx);

/* Connect and handshake - fails if must-staple cert has no OCSP response */
SocketTLS_enable(sock, ctx);
SocketTLS_handshake_auto(sock);

kTLS (Kernel TLS) Offload

kTLS lagert die TLS-Verschlüsselung/-Entschlüsselung an den Linux-Kernel aus, um die Leistung zu verbessern.```c #include "tls/SocketTLS.h"

/* Check if kTLS is available on this system */ if (SocketTLS_ktls_available()) { printf("kTLS available - optimal async I/O\n"); }

/* Enable kTLS before handshake / SocketTLS_enable(sock, ctx); SocketTLS_enable_ktls(sock); / Request kTLS offload */ SocketTLS_handshake_auto(sock);

/* Check if offload is active after handshake */ if (SocketTLS_is_ktls_tx_active(sock)) { printf("TX offload active\n"); } if (SocketTLS_is_ktls_rx_active(sock)) { printf("RX offload active\n"); }

/* Zero-copy file transfer with kTLS (uses SSL_sendfile internally) */ int file_fd = open("largefile.bin", O_RDONLY); off_t offset = 0; ssize_t sent = SocketTLS_sendfile(sock, file_fd, offset, file_size); close(file_fd);

root@kitploit:~
**kTLS Anforderungen:**
| Funktion | Anforderung |
|---------|-------------|
| TX offload | Linux 4.13+, OpenSSL 3.0+ mit enable-ktls |
| RX offload | Linux 4.17+ |
| ChaCha20 | Linux 5.11+ |
| Ciphers | AES-GCM-128/256, ChaCha20-Poly1305 |

### TLS 1.3 0-RTT Early Data```c
#include "tls/SocketTLS.h"
#include "tls/SocketTLSContext.h"

/* Server: Enable 0-RTT early data reception */
SocketTLSContext_T srv_ctx = SocketTLSContext_new_server("cert.pem", "key.pem", NULL);
SocketTLSContext_enable_early_data(srv_ctx, 16384);  /* Max 16KB early data */

/* Client: Send early data during handshake */
SocketTLS_enable(sock, ctx);
SocketTLS_set_hostname(sock, "example.com");

/* Write early data (before handshake completes) */
size_t written = 0;
int ret = SocketTLS_write_early_data(sock, "GET / HTTP/1.1\r\n\r\n", 18, &written);
if (ret == 1) {
    printf("Sent %zu bytes as early data\n", written);
}

/* Complete handshake */
SocketTLS_handshake_auto(sock);

/* Check if early data was accepted */
SocketTLS_EarlyDataStatus status = SocketTLS_get_early_data_status(sock);
if (status == SOCKET_EARLY_DATA_REJECTED) {
    /* Server rejected - resend via normal I/O */
    SocketTLS_send(sock, "GET / HTTP/1.1\r\n\r\n", 18);
}

/* Server: Read early data during handshake */
unsigned char early_buf[4096];
size_t readbytes = 0;
ret = SocketTLS_read_early_data(srv_sock, early_buf, sizeof(early_buf), &readbytes);

Sicherheitswarnung: 0-RTT ist NICHT replay-geschützt. Nur für idempotente Operationen verwenden.

TLS 1.3 KeyUpdate (Key Rotation)```c

#include "tls/SocketTLS.h"

/* For long-lived connections, rotate keys periodically for forward secrecy */

/* Request key update (local only) */ int ret = SocketTLS_request_key_update(sock, 0);

/* Request key update and ask peer to also rotate */ ret = SocketTLS_request_key_update(sock, 1);

/* Monitor key rotations performed */ int count = SocketTLS_get_key_update_count(sock); printf("Key rotations: %d\n", count);

root@kitploit:~
**Empfohlene Verwendung:**
- Datenbankverbindungen, die Stunden/Tage geöffnet sind
- VPN-Tunnel
- Beständige WebSocket-Verbindungen
- Rotation jede Stunde oder nach jeweils 1 GB übertragener Daten

### TLS-Leistungsoptimierungen```c
#include "tls/SocketTLS.h"
#include "tls/SocketTLSContext.h"

/* TCP handshake optimization - apply before TLS handshake */
SocketTLS_optimize_handshake(sock);  /* Sets TCP_NODELAY + TCP_QUICKACK */

/* After bulk transfer, optionally restore defaults */
SocketTLS_restore_tcp_defaults(sock);  /* Re-enables Nagle */

/* Session cache sharding for multi-threaded servers */
SocketTLSContext_create_sharded_cache(ctx, 
    8,      /* Number of shards (match thread count) */
    1000,   /* Sessions per shard */
    300);   /* Timeout in seconds */

/* Get aggregate statistics from sharded cache */
size_t total_hits, total_misses, total_stores;
SocketTLSContext_get_sharded_stats(ctx, &total_hits, &total_misses, &total_stores);

/* TLS buffer pool for high-connection scenarios */
Arena_T arena = Arena_new();
TLSBufferPool_T pool = TLSBufferPool_new(16384, 100, arena);  /* 16KB buffers, 100 count */

/* Acquire buffer for connection */
void *buf = TLSBufferPool_acquire(pool);
/* ... use buffer for TLS I/O ... */
TLSBufferPool_release(pool, buf);

/* Check pool statistics */
size_t total, in_use, available;
TLSBufferPool_stats(pool, &total, &in_use, &available);

TLSBufferPool_free(&pool);
Arena_dispose(&arena);

CRL Auto-Refresh```c

#include "tls/SocketTLSContext.h"

/* Callback for refresh notifications */ void crl_refresh_callback(SocketTLSContext_T ctx, const char *path, int success, void *data) { if (!success) { fprintf(stderr, "CRL refresh failed for %s\n", path); } }

/* Configure automatic CRL refresh (minimum 60 seconds) / SocketTLSContext_set_crl_auto_refresh(ctx, "/path/to/crl.pem", 3600, / Refresh every hour */ crl_refresh_callback, NULL);

/* In event loop: check if refresh is due / while (running) { / ... process events ... */ SocketTLSContext_crl_check_refresh(ctx);

root@kitploit:~
/* Get time until next refresh for poll timeout optimization */
int64_t next_ms = SocketTLSContext_crl_next_refresh_ms(ctx);

}

/* Cancel auto-refresh (retains currently loaded CRL) */ SocketTLSContext_cancel_crl_auto_refresh(ctx);

root@kitploit:~
### Zero-Copy-Dateiübertragung```c
int file_fd = open("largefile.bin", O_RDONLY);
struct stat st;
fstat(file_fd, &st);

off_t offset = 0;
ssize_t sent = Socket_sendfileall(socket, file_fd, &offset, st.st_size);
close(file_fd);

Scatter/Gather I/O```c

struct iovec iov[3]; iov[0].iov_base = header; iov[0].iov_len = header_len; iov[1].iov_base = body; iov[1].iov_len = body_len; iov[2].iov_base = footer; iov[2].iov_len = footer_len;

/* Send all data atomically */ ssize_t sent = Socket_sendvall(socket, iov, 3);

root@kitploit:~
### Unix Domain Sockets mit FD-Übergabe```c
#include "socket/Socket.h"

/* Stream socket pair for IPC */
Socket_T sock1, sock2;
SocketPair_new(SOCK_STREAM, &sock1, &sock2);

/* Server socket */
Socket_T server = Socket_new(AF_UNIX, SOCK_STREAM, 0);
Socket_bind_unix(server, "/tmp/my.sock");
Socket_listen(server, 10);

/* Client connection */
Socket_T client = Socket_new(AF_UNIX, SOCK_STREAM, 0);
Socket_connect_unix(client, "/tmp/my.sock");

/* Get peer credentials (Linux only) */
int peer_pid = Socket_getpeerpid(accepted);
int peer_uid = Socket_getpeeruid(accepted);
int peer_gid = Socket_getpeergid(accepted);

/* Abstract namespace (Linux only - prefix with @) */
Socket_bind_unix(server, "@abstract-socket");

/* File descriptor passing (SCM_RIGHTS) */
int fd_to_pass = open("/etc/passwd", O_RDONLY);
Socket_sendfd(sock1, fd_to_pass);
close(fd_to_pass);

/* Receive passed FD */
int received_fd;
Socket_recvfd(sock2, &received_fd);
/* received_fd is now a valid FD in this process */
close(received_fd);

/* Multiple FD passing */
int fds[3] = {fd1, fd2, fd3};
Socket_sendfds(sock1, fds, 3);

int received_fds[3];
size_t num_fds;
Socket_recvfds(sock2, received_fds, 3, &num_fds);

Kryptografische Dienstprogramme```c

#include "core/SocketCrypto.h"

/* SHA-256 hash */ unsigned char hash[SOCKET_CRYPTO_SHA256_SIZE]; SocketCrypto_sha256(data, data_len, hash);

/* HMAC-SHA256 */ unsigned char mac[SOCKET_CRYPTO_SHA256_SIZE]; SocketCrypto_hmac_sha256(key, key_len, data, data_len, mac);

/* Base64 encoding */ size_t encoded_len = SocketCrypto_base64_encoded_size(data_len); char *encoded = malloc(encoded_len); SocketCrypto_base64_encode(data, data_len, encoded, encoded_len);

/* Cryptographically secure random */ unsigned char random_bytes[32]; SocketCrypto_random_bytes(random_bytes, sizeof(random_bytes));

/* Constant-time comparison (prevents timing attacks) / if (SocketCrypto_secure_compare(expected, actual, len)) { / Match */ }

/* Secure memory clearing */ SocketCrypto_secure_clear(password, password_len);

root@kitploit:~
### Beobachtbarkeit - Protokollierung```c
#include "core/SocketUtil.h"

/* Custom logging callback */
void my_logger(void *userdata, SocketLogLevel level,
               const char *component, const char *message) {
    printf("[%s] %s: %s\n", SocketLog_levelname(level), component, message);
}
SocketLog_setcallback(my_logger, NULL);

/* Set minimum log level */
SocketLog_setlevel(SOCKET_LOG_DEBUG);

/* Use convenience macros */
#define SOCKET_LOG_COMPONENT "MyApp"
SOCKET_LOG_INFO_MSG("Server started on port %d", port);
SOCKET_LOG_ERROR_MSG("Connection failed: %s", strerror(errno));

/* Correlation IDs for distributed tracing */
SocketLogContext ctx = {0};
strncpy(ctx.request_id, "req-12345", sizeof(ctx.request_id) - 1);
strncpy(ctx.trace_id, "trace-abcde", sizeof(ctx.trace_id) - 1);
SocketLog_setcontext(&ctx);
SOCKET_LOG_INFO_MSG("Processing request");  /* Includes correlation IDs */
SocketLog_clearcontext();

Beobachtbarkeit - Metriken```c

#include "core/SocketMetrics.h"

/* Record metrics */ SocketMetrics_counter_inc(SOCKET_CTR_SOCKET_CREATED); SocketMetrics_gauge_set(SOCKET_GAU_POOL_ACTIVE_CONNECTIONS, 42); SocketMetrics_histogram_observe(SOCKET_HIST_HTTP_CLIENT_REQUEST_LATENCY_MS, 125.0);

/* Get percentiles */ double p99 = SocketMetrics_histogram_percentile(SOCKET_HIST_HTTP_CLIENT_REQUEST_LATENCY_MS, 99.0);

/* Export to Prometheus */ char buffer[65536]; size_t len = SocketMetrics_export_prometheus(buffer, sizeof(buffer));

/* Export to StatsD */ SocketMetrics_export_statsd(buffer, sizeof(buffer), "myapp.socket");

/* Export to JSON */ SocketMetrics_export_json(buffer, sizeof(buffer));

/* Get complete snapshot */ SocketMetrics_Snapshot snapshot; SocketMetrics_get(&snapshot);

/* Reset metrics */ SocketMetrics_reset();

/* Socket count and peak tracking / int current = SocketMetrics_get_socket_count(); int peak = SocketMetrics_get_peak_connections(); SocketMetrics_reset_peaks(); / Reset high watermark */

root@kitploit:~
### Pro-Socket-Statistiken

Verfolgen Sie E/A-Statistiken für einzelne Sockets:```c
#include "socket/Socket.h"

Socket_T sock = Socket_new(AF_INET, SOCK_STREAM, 0);
Socket_connect(sock, "example.com", 80);

/* ... send/recv operations ... */

/* Get per-socket statistics */
SocketStats_T stats;
Socket_getstats(sock, &stats);

printf("Bytes: %zu sent, %zu received\n",
       (size_t)stats.bytes_sent, (size_t)stats.bytes_received);
printf("Packets: %zu sent, %zu received\n",
       (size_t)stats.packets_sent, (size_t)stats.packets_received);
printf("Errors: %zu send, %zu recv\n",
       (size_t)stats.send_errors, (size_t)stats.recv_errors);
printf("Last activity: send=%lld ms, recv=%lld ms ago\n",
       (long long)(Socket_get_monotonic_ms() - stats.last_send_time_ms),
       (long long)(Socket_get_monotonic_ms() - stats.last_recv_time_ms));

/* RTT estimation (Linux only via TCP_INFO) */
if (stats.rtt_us >= 0) {
    printf("RTT: %.2f ms (var: %.2f ms)\n",
           stats.rtt_us / 1000.0, stats.rtt_var_us / 1000.0);
}

/* Reset statistics for next interval */
Socket_resetstats(sock);

Socket_free(&sock);

Erweiterte TCP-Optionen```c

/* Congestion control algorithm (Linux only) */ Socket_setcongestion(socket, "bbr"); char algo[16]; Socket_getcongestion(socket, algo, sizeof(algo));

/* TCP Fast Open (Linux 3.7+, FreeBSD 10.0+, macOS 10.11+) */ Socket_setfastopen(socket, 1);

/* TCP user timeout (Linux 2.6.37+) / Socket_setusertimeout(socket, 30000); / 30 seconds */

/* TCP keepalive / Socket_setkeepalive(socket, 60, 10, 5); / idle=60s, interval=10s, count=5 */

/* Disable Nagle's algorithm */ Socket_setnodelay(socket, 1);

/* Buffer sizes */ Socket_setrcvbuf(socket, 262144); Socket_setsndbuf(socket, 262144);

/* SYN flood protection / Socket_setdeferaccept(socket, 10); / Wait 10s for data before accept() */

root@kitploit:~
## Architektur

### Modulorganisation```
include/
├── core/          # Foundation layer
│   ├── Arena.h          # Arena memory management
│   ├── Except.h         # Exception handling
│   ├── SocketConfig.h   # Configuration constants
│   ├── SocketCrypto.h   # Cryptographic utilities
│   ├── SocketIPTracker.h # Per-IP connection tracking
│   ├── SocketMetrics.h  # Production metrics (counters, gauges, histograms)
│   ├── SocketRateLimit.h # Token bucket rate limiting
│   ├── SocketRetry.h    # Generic retry with exponential backoff
│   ├── SocketSecurity.h # Security utilities
│   ├── SocketSYNProtect.h # SYN flood protection
│   ├── SocketTimer.h    # Timer management
│   ├── SocketUTF8.h     # UTF-8 validation
│   └── SocketUtil.h     # Logging, error handling, utilities
├── socket/        # Core I/O layer
│   ├── Socket.h         # TCP/Unix domain sockets
│   ├── SocketAsync.h    # Async I/O (io_uring/kqueue)
│   ├── SocketBuf.h      # Circular buffer
│   ├── SocketCommon.h   # Shared socket base
│   ├── SocketDgram.h    # UDP sockets
│   ├── SocketHappyEyeballs.h # RFC 8305 connection racing
│   ├── SocketIO.h       # I/O helpers
│   ├── SocketProxy.h    # HTTP CONNECT/SOCKS proxy
│   ├── SocketReconnect.h # Auto-reconnection
│   └── SocketWS.h       # WebSocket (RFC 6455)
├── dns/           # DNS layer
│   ├── SocketDNS.h      # Async DNS resolution
│   ├── SocketDNSoverTLS.h # DNS-over-TLS (RFC 7858)
│   ├── SocketDNSoverHTTPS.h # DNS-over-HTTPS (RFC 8484)
│   ├── SocketDNSSEC.h   # DNSSEC validation (RFC 4033-4035)
│   ├── SocketDNSCookie.h # DNS cookies (RFC 7873)
│   ├── SocketDNSResolver.h # High-level resolver API
│   ├── SocketDNSWire.h  # Wire format encoding/decoding
│   ├── SocketDNSTransport.h # UDP/TCP transport layer
│   ├── SocketDNSNegCache.h # Negative response caching
│   └── SocketDNSError.h # Extended DNS errors (RFC 8914)
├── poll/          # Event system
│   └── SocketPoll.h     # Cross-platform polling
├── pool/          # Connection management
│   └── SocketPool.h     # Connection pooling
├── tls/           # Security layer
│   ├── SocketTLS.h      # TLS operations
│   ├── SocketTLSContext.h # TLS context management
│   ├── SocketTLSConfig.h # TLS configuration constants
│   ├── SocketDTLS.h     # DTLS operations
│   ├── SocketDTLSContext.h # DTLS context management
│   └── SocketDTLSConfig.h # DTLS configuration constants
├── http/          # HTTP protocol stack
│   ├── SocketHTTP.h     # HTTP core (RFC 9110)
│   ├── SocketHTTP1.h    # HTTP/1.1 (RFC 9112)
│   ├── SocketHPACK.h    # HPACK (RFC 7541)
│   ├── SocketHTTP2.h    # HTTP/2 (RFC 9113)
│   ├── SocketHTTPClient.h # HTTP client API
│   └── SocketHTTPServer.h # HTTP server API
├── quic/          # QUIC transport layer
│   ├── SocketQUICConnection.h # Connection management (RFC 9000)
│   ├── SocketQUICStream.h   # Stream multiplexing
│   ├── SocketQUICPacket.h   # Packet parsing/serialization
│   ├── SocketQUICFrame.h    # Frame encoding/decoding
│   ├── SocketQUICHandshake.h # TLS 1.3 handshake integration
│   ├── SocketQUICFlow.h     # Flow control
│   ├── SocketQUICLoss.h     # Loss detection (RFC 9002)
│   ├── SocketQUICMigration.h # Path migration
│   └── SocketQUICVersion.h  # Version negotiation
└── simple/        # Return-code based convenience API
    ├── SocketSimple.h       # Core simple socket API
    ├── SocketSimple-http.h  # Simple HTTP client
    ├── SocketSimple-tls.h   # Simple TLS connections
    ├── SocketSimple-ws.h    # Simple WebSocket
    └── SocketSimple-dns.h   # Simple DNS resolution

Schichtenarchitektur

  1. Foundation: Arena (Speicher), Except (Fehler), SocketCrypto (Kryptografische Primitive)
  2. Utilities: SocketUtil (Protokollierung, Metriken, Ereignisse, Fehlerbehandlung), SocketTimer, SocketRateLimit, SocketUTF8, SocketRetry
  3. Basisabstraktion: SocketCommon (Geteilte Basis SocketBase_T für Socket/SocketDgram)
  4. Kern-I/O: Socket (TCP/Unix), SocketDgram (UDP), SocketBuf (Puffer), SocketIO (I/O-Helfer)

Thread-Sicherheit

Signalbehandlung

SIGPIPE (Automatisch)

Keine Anwendungsaktion erforderlich. Die Bibliothek behandelt SIGPIPE intern:

PlattformMechanismusAngewandt bei
Linux/FreeBSDMSG_NOSIGNAL-FlagBei jedem Sendevorgang
BSD/macOSSO_NOSIGPIPE-OptionBei Socket-Erstellung

Anwendungen müssen NICHT signal(SIGPIPE, SIG_IGN) aufrufen.

Für Legacy-Code oder Defense-in-Depth wird eine optionale Komfortfunktion bereitgestellt:```c // Optional - not required Socket_ignore_sigpipe();

root@kitploit:~
### Sanftes Herunterfahren

Die Bibliothek installiert **KEINE** Signalhandler. Anwendungen müssen selbst für das Abfangen von Herunterfahrsignalen sorgen. Empfohlenes Muster unter Verwendung des self-pipe trick:```c
#include <signal.h>
#include <unistd.h>

static int signal_pipe[2];

/* Async-signal-safe handler - only writes to pipe */
static void shutdown_handler(int signo) {
    (void)signo;
    char byte = 1;
    (void)write(signal_pipe[1], &byte, 1);  /* write() is async-signal-safe */
}

int main(void) {
    pipe(signal_pipe);
    fcntl(signal_pipe[0], F_SETFL, O_NONBLOCK);
    fcntl(signal_pipe[1], F_SETFL, O_NONBLOCK);
    
    struct sigaction sa = {0};
    sa.sa_handler = shutdown_handler;
    sigemptyset(&sa.sa_mask);
    sigaction(SIGINT, &sa, NULL);
    sigaction(SIGTERM, &sa, NULL);
    
    /* Add signal pipe to poll set */
    SocketPoll_add_fd(poll, signal_pipe[0], POLL_READ, NULL);
    
    /* In event loop, check for signal pipe readability */
    /* Then use SocketPool_drain() for graceful connection draining */
}

Erstellen

Anforderungen

  • CMake 3.10+
  • C11-Compiler mit GNU-Erweiterungen und pthread-Unterstützung
  • POSIX-kompatibles System
  • OpenSSL 1.1.1+ oder LibreSSL (optional, für TLS/DTLS-Unterstützung)
  • zlib (optional, für HTTP-Kompression und WebSocket permessage-deflate)

Build-Befehle```bash

Configure

cmake -S . -B build

Build

cmake --build build -j

Run tests

cd build && ctest --output-on-failure

Generate API documentation (requires Doxygen)

cmake --build build --target doc

Install (optional)

cmake --install build --prefix /usr/local

root@kitploit:~
### Build-Optionen

| Option | Beschreibung | Standard |
|--------|-------------|---------|
| `CMAKE_BUILD_TYPE` | Debug oder Release | Debug |
| `ENABLE_TLS` | TLS/DTLS-Unterstützung aktivieren | ON (automatische Erkennung) |
| `ENABLE_HTTP_COMPRESSION` | gzip/deflate/brotli aktivieren | OFF |
| `ENABLE_SANITIZERS` | ASan + UBSan aktivieren | OFF |
| `ENABLE_ASAN` | Nur AddressSanitizer aktivieren | OFF |
| `ENABLE_UBSAN` | Nur UndefinedBehaviorSanitizer aktivieren | OFF |
| `ENABLE_COVERAGE` | gcov-Abdeckung aktivieren | OFF |
| `ENABLE_FUZZING` | Fuzz-Tests aktivieren (erfordert Clang) | OFF |

### Poll-Backend-Auswahl

Das Poll-Backend wird automatisch basierend auf der Plattform ausgewählt:
- **Linux** - epoll (schnellste für Linux)
- **BSD/macOS** - kqueue
- **Andere POSIX** - poll(2)-Fallback

### Async-I/O-Backend-Auswahl

- **Linux 5.1+** - io_uring (echtes async)
- **BSD/macOS** - kqueue AIO
- **Fallback** - Edge-getriggertes Polling

## Tests und Qualität

### Test-Suite

Die Bibliothek enthält umfassende Tests in `src/test/`:

| Kategorie | Testdateien |
|----------|------------|
| Kern | `test_arena.c`, `test_except.c`, `test_crypto.c`, `test_utf8.c`, `test_ratelimit.c` |
| Socket | `test_socket.c`, `test_socketdgram.c`, `test_socketbuf.c` |
| Netzwerk | `test_socketpoll.c`, `test_socketpool.c`, `test_socketdns.c`, `test_socketerror.c` |
| Verbindung | `test_happy_eyeballs.c`, `test_reconnect.c`, `test_proxy.c`, `test_proxy_integration.c` |
| HTTP | `test_http_core.c`, `test_http1_parser.c`, `test_hpack.c`, `test_http2.c`, `test_http_client.c`, `test_http_integration.c`, `test_http2_integration.c` |
| WebSocket | `test_websocket.c`, `test_ws_integration.c` |
| TLS/DTLS | `test_tls_integration.c`, `test_tls_phase4.c`, `test_tls_pinning.c`, `test_tls_crl.c`, `test_tls_ct.c`, `test_dtls_integration.c`, `test_dtls_cookie.c` |
| Sicherheit | `test_synprotect.c`, `test_security.c`, `test_signals.c` |
| Integration | `test_integration.c`, `test_async.c`, `test_threadsafety.c`, `test_coverage.c` |

### Fuzz-Tests

130+ Fuzz-Harnesses in `src/fuzz/` abdeckend:
- HTTP/1.1-Parser und Schutz vor Request-Smuggling
- HTTP/2-Frame-Parsing und HPACK-Kodierung
- WebSocket-Framing und Permessage-Deflate
- URI-Parsing und -Validierung
- UTF-8-Validierung
- TLS/DTLS-Handshake und I/O-Operationen
- TLS-Session-Tickets, ALPN, SNI, CRL-Verwaltung
- DTLS-Cookie-Generierung und -Verifizierung
- Zertifikat-Pinning und -Parsing
- Pfadvalidierung und Sicherheitsprüfungen```bash
# Build with fuzzing
cmake -S . -B build -DENABLE_FUZZING=ON -DCMAKE_C_COMPILER=clang
cmake --build build

Testabdeckung

Die Bibliothek bietet eine umfassende Testabdeckung:

  • 140+ Unit-Tests für alle wichtigen Funktionen
  • Fuzzing-Harnesses für Protokoll-Parsing und Puffer-Operationen
  • Integrationstests für End-to-End-Funktionalität
  • Stresstests für Verbindungspools und Hochlastszenarien

Neue Funktionen, die in den letzten Erweiterungen hinzugefügt wurden, umfassen:

  • High-level-Komfortfunktionen für TCP/Unix-Socket-Einrichtung
  • Socket-Statistiken und Metriksammlung
  • Verbindungspool-Verwaltung und Gesundheitsüberwachung
  • DNS-Caching und -Konfiguration
  • E/A-Timeout-Varianten und erweiterte Operationen
  • TLS-Sitzungsverwaltung und Zertifikatsinspektion
  • TLS-Leistungsoptimierungen (kTLS, 0-RTT, KeyUpdate, Session-Sharding)
  • OCSP-Stapling mit Must-Staple-Unterstützung (RFC 7633)
  • Certificate-Transparency-Validierung (RFC 6962)
  • CRL-Auto-Aktualisierung mit konfigurierbaren Intervallen
  • Zertifikats-Pinning mit zeitkonstanter Verifizierung
  • DTLS-Cookie-Austausch zum DoS-Schutz
  • HTTP-Client/Server mit JSON-Unterstützung und WebSocket-Upgrades
  • Buffer-Kompaktierung, Scatter-Gather-I/O und Zeilenlesen
  • Asynchrone E/A-Batch-Operationen und Backend-Auswahl
  • Event-System-Introspection und Timer-Steuerung

Sanitizer

Alle Tests bestehen mit:

  • AddressSanitizer (ASan)
  • UndefinedBehaviorSanitizer (UBSan)
  • Valgrind-Speicherprüfung```bash

Build with sanitizers

cmake -S . -B build -DENABLE_SANITIZERS=ON cmake --build build cd build && ctest --output-on-failure

Valgrind

valgrind --leak-check=full --track-fds=yes
--suppressions=../valgrind.supp ./test_socket

root@kitploit:~
### Continuous Integration

GitHub Actions Pipeline (`.github/workflows/ci.yml`):

| Auftrag | Plattform | Beschreibung |
|---------|-----------|--------------|
| `build` | Ubuntu | Debug- und Release-Builds |
| `sanitizers` | Ubuntu | ASan, UBSan, kombiniert |
| `valgrind` | Ubuntu | Speicherleckprüfung |
| `macos` | macOS | kqueue-Backend-Tests |
| `macos-sanitizers` | macOS | Plattformübergreifende Sanitizer |
| `coverage` | Ubuntu | Codeabdeckung mit lcov |
| `static-analysis` | Ubuntu | cppcheck + clang-tidy |

## Ausnahmetypen

### Kernausnahmen
- `Socket_Failed` – Allgemeiner Socket-Operationsfehler
- `Socket_Closed` – Verbindung durch Gegenstelle geschlossen
- `SocketUnix_Failed` – Unix-Socket-Operationsfehler
- `SocketDgram_Failed` – UDP-Socket-Operationsfehler
- `SocketPoll_Failed` – Ereignisabfragefehler
- `SocketPool_Failed` – Connection-Pool-Operationsfehler
- `SocketDNS_Failed` – DNS-Auflösungsfehler
- `SocketTimer_Failed` – Timer-Operationsfehler
- `SocketRateLimit_Failed` – Fehler des Ratenbegrenzers
- `SocketRetry_Failed` – Fehler beim Wiederholungsvorgang
- `SocketAsync_Failed` – Asynchroner E/A-Fehler
- `SocketCrypto_Failed` – Kryptografischer Operationsfehler

### Verbindungsausnahmen
- `SocketHE_Failed` – Happy-Eyeballs-Verbindungsfehler
- `SocketReconnect_Failed` – Fehler beim Wiederverbindungsvorgang
- `SocketProxy_Failed` – Proxy-Verbindungsfehler

### TLS/DTLS-Ausnahmen
- `SocketTLS_Failed` – Allgemeiner TLS-Operationsfehler
- `SocketTLS_HandshakeFailed` – TLS-Handshake-Fehler
- `SocketTLS_VerifyFailed` – Zertifikatsprüfungsfehler
- `SocketTLS_ProtocolError` – TLS-Protokollfehler
- `SocketTLS_ShutdownFailed` – TLS-Beendigungsfehler
- `SocketTLS_PinVerifyFailed` – Fehler bei der Zertifikatspinning-Prüfung
- `SocketDTLS_Failed` – Allgemeiner DTLS-Operationsfehler
- `SocketDTLS_HandshakeFailed` – DTLS-Handshake-Fehler
- `SocketDTLS_VerifyFailed` – DTLS-Zertifikatsprüfungsfehler
- `SocketDTLS_CookieFailed` – DTLS-Cookie-Austauschfehler
- `SocketDTLS_TimeoutExpired` – DTLS-Handshake-Timeout
- `SocketDTLS_ShutdownFailed` – DTLS-Beendigungsfehler

### HTTP-Ausnahmen
- `SocketHTTP_ParseError` – HTTP-Parsing-Fehler
- `SocketHTTP_InvalidURI` – Ungültige URI
- `SocketHTTP_InvalidHeader` – Ungültiger Header
- `SocketHTTP1_ParseError` – HTTP/1.1-Parsing-Fehler
- `SocketHPACK_Failed` – HPACK-Komprimierungsfehler
- `SocketHTTP2_ProtocolError` – HTTP/2-Protokollfehler
- `SocketHTTP2_StreamError` – HTTP/2-Stream-Fehler
- `SocketHTTP2_FlowControlError` – HTTP/2-Flusskontrollfehler
- `SocketHTTPClient_Failed` – HTTP-Client-Fehler
- `SocketHTTPClient_Timeout` – HTTP-Client-Timeout
- `SocketHTTPClient_TLSFailed` – TLS-Fehler des HTTP-Clients
- `SocketHTTPClient_DNSFailed` – DNS-Fehler des HTTP-Clients
- `SocketHTTPClient_ConnectFailed` – Verbindungsfehler des HTTP-Clients
- `SocketHTTPClient_ProtocolError` – Protokollfehler des HTTP-Clients
- `SocketHTTPClient_TooManyRedirects` – Zu viele Weiterleitungen
- `SocketHTTPClient_ResponseTooLarge` – Antwortgrößenlimit überschritten
- `SocketHTTPServer_Failed` – HTTP-Server-Fehler

### WebSocket-Ausnahmen
- `SocketWS_Failed` – WebSocket-Operationsfehler
- `SocketWS_ProtocolError` – WebSocket-Protokollfehler
- `SocketWS_Closed` – WebSocket-Verbindung geschlossen

### Sicherheitsausnahmen
- `SocketSYNProtect_Failed` – SYN-Schutzfehler

## Lizenz

Siehe `LICENSE` für Nutzungsdetails.
Tool herunterladen
MerkmalLinuxBSD/macOSAusweichverfahren
Ereignisabfrageepollkqueuepoll(2)
Asynchrone I/Oio_uring (5.1+)kqueue AIOedge-triggered
TCP Fast Open3.7+10.0+/10.11+deaktiviert
Überlastregelungkonfigurierbar--
Peer-AnmeldeinformationenSO_PEERCREDLOCAL_PEERCRED-
SYN-SchutzTCP_DEFER_ACCEPTSO_ACCEPTFILTERuserspace
  • DNS: SocketDNS (Asynchrones DNS mit Worker-Threads), SocketDNSoverTLS, SocketDNSoverHTTPS, SocketDNSSEC
  • Ereignissystem: SocketPoll (epoll/kqueue/poll-Abstraktion), SocketAsync (Asynchrone I/O-Integration)
  • Verbindungshelfer: SocketHappyEyeballs (RFC 8305), SocketReconnect (Automatische Wiederverbindung), SocketProxy (HTTP CONNECT, SOCKS4/5)
  • Sicherheit: SocketSYNProtect (SYN-Überflutungsschutz), SocketIPTracker (Pro-IP-Begrenzungen)
  • Anwendung: SocketPool (Verbindungsverwaltung)
  • TLS: SocketTLS (TLS-I/O), SocketTLSContext (Kontextverwaltung), SocketDTLS, SocketDTLSContext
  • HTTP: SocketHTTP, SocketHTTP1, SocketHPACK, SocketHTTP2, SocketHTTPClient, SocketHTTPServer
  • WebSocket: SocketWS (RFC 6455 mit Permessage-Deflate)
  • QUIC: SocketQUICConnection, SocketQUICStream, SocketQUICPacket, SocketQUICHandshake, SocketQUICLoss
  • Einfache API: SocketSimple (Rückgabecode-basierte Wrapper für alle Module – kein TRY/EXCEPT erforderlich)
  • KomponenteThread-SicherheitAnmerkungen
    Socket-OperationenPro SocketEin Thread pro Socket empfohlen
    FehlerberichterstattungThread-lokalSicher für gleichzeitige Nutzung
    SocketPollThreadsicherDurch Mutexe geschützt
    SocketPoolThreadsicherDurch Mutexe geschützt
    SocketDNSThreadsicherVerwendet Thread-Pool
    SocketTimerThreadsicherIntegriert mit Poll
    SocketRateLimitThreadsicherInterner Mutex
    SocketRetryNICHT threadsicherEine Instanz pro Thread
    Metriken/ProtokollierungThreadsicherAtomare Operationen
    SocketCryptoThreadsicherKein globaler Zustand
    SocketUTF8ThreadsicherKein globaler Zustand
    SocketHappyEyeballsNICHT threadsicherEine Instanz pro Thread
    SocketReconnectNICHT threadsicherEine Instanz pro Thread
    SocketProxyNICHT threadsicherEine Instanz pro Thread
    SocketWSNICHT threadsicherEine Instanz pro Thread
    SocketSYNProtectThreadsicherInterner Mutex für Zustandsänderungen
    HTTP/2-VerbindungenNICHT threadsicherEine Instanz pro Thread
    HTTP-ClientThreadsicherAnfrageinstanzen sind NICHT threadsicher
    HTTP-ServerNICHT threadsicherEine Instanz pro Thread
    TLS/DTLS-KontexteThreadsicherSchreibgeschützt nach Einrichtung; Sitzungscache-Mutex geschützt
    TLS/DTLS-SocketsPro SocketEin Thread pro TLS-Socket
    TLSBufferPoolThreadsicherInterner Mutex