maintenant à deux voies!
This commit is contained in:
COLIN Cyril
parent
8b350efed2
commit
0c97dac0d1
@ -1,4 +1,4 @@
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CC := gcc -Wall -Wextra -Wpedantic -Wshadow=local -Iinclude -Isrc -g -std=c11
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CC := gcc -Wall -Wextra -Wpedantic -Iinclude -Isrc -g -std=c11
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# pkg-config
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# LIBS :=
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@ -11,25 +11,30 @@
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#include <string.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/select.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#define BUFSIZE 1024
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int ext_out(int port) {
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static int setup_out(int port) {
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/* Create the socket. */
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int server = socket(AF_INET6, SOCK_STREAM, 0);
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if (server == -1) {
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perror("socket");
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exit(1);
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}
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/* Enable socket re-use, makes debugging easier. */
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setsockopt(server, SOL_SOCKET, SO_REUSEADDR, &(int) {1}, sizeof (int));
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/* Bind to any local IPv6 address on port PORT. */
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struct sockaddr_in6 server_addr = {0};
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server_addr.sin6_family = AF_INET6;
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server_addr.sin6_port = htons(port);
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@ -38,6 +43,8 @@ int ext_out(int port) {
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perror("bind");
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exit(1);
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}
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/* Pretty print the matched address. */
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char server_addr_pretty[INET6_ADDRSTRLEN] = "";
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inet_ntop(AF_INET6, &(server_addr.sin6_addr), server_addr_pretty, sizeof server_addr_pretty);
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printf("Écoute sur : %s\n", server_addr_pretty);
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@ -47,87 +54,184 @@ int ext_out(int port) {
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exit(1);
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}
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return server;
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}
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static int accept_client(int server) {
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/* Wait for a connection attempt. */
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struct sockaddr_in6 client_addr;
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socklen_t client_addr_len;
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puts("Attente d’un client.");
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int client = accept(server, (struct sockaddr *) &client_addr, &client_addr_len);
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/* We only serve one peer, no need to keep the server socket
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* open. */
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close(server);
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/* Pretty print the peer’s address */
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char client_addr_pretty[INET6_ADDRSTRLEN] = "";
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inet_ntop(AF_INET6, &(client_addr.sin6_addr), client_addr_pretty, sizeof client_addr_pretty);
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printf("Client connecté : %s\n", client_addr_pretty);
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return client;
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/* char buf[BUFSIZE]; */
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/* ssize_t n; */
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/* while (1) { */
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/* n = read(client, buf, sizeof buf); */
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/* if (n == -1) { */
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/* perror("read"); */
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/* exit(1); */
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/* } */
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/* n = write(out, buf, n); */
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/* if (n == -1) { */
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/* perror("write"); */
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/* exit(1); */
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/* } */
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/* } */
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/* close(client); */
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}
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int ext_in(const char addr[], int port) {
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int ext_out(int port) {
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int server = setup_out(port);
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return accept_client(server);
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}
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static int setup_in() {
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int s = socket(AF_INET6, SOCK_STREAM, 0);
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if (s == -1) {
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perror("socket");
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exit(1);
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}
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return s;
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}
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static int try_connect(int s, const char addr[], int port) {
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struct sockaddr_in6 sa = {0};
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sa.sin6_family = AF_INET6;
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sa.sin6_port = htons(port);
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inet_pton(AF_INET6, addr, &sa.sin6_addr);
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puts("Connexion.");
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while (connect(s, (struct sockaddr *) &sa, sizeof sa) == -1) {
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if (connect(s, (struct sockaddr *) &sa, sizeof sa) == -1) {
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perror("connect");
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sleep(1);
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return 0;
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}
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char addr_pretty[INET6_ADDRSTRLEN] = "";
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inet_ntop(AF_INET6, &(sa.sin6_addr), addr_pretty, sizeof addr_pretty);
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printf("Connecté à : %s\n", addr_pretty);
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return 1;
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}
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int ext_in(const char addr[], int port) {
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int s = setup_in();
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/* Attempt a connection every second (waiting for the server to
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* start). */
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while (!try_connect(s, addr, port)) {
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sleep(1);
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}
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return s;
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/* char buf[BUFSIZE]; */
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/* ssize_t n; */
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/* while (1) { */
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/* n = read(in, buf, sizeof buf); */
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/* if (n == -1) { */
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/* perror("read"); */
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/* exit(1); */
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/* } */
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/* n = write(s, buf, n); */
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/* if (n == -1) { */
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/* perror("write"); */
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/* exit(1); */
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/* } */
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/* } */
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/* close(s); */
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}
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void ext_bidir(const char addr[], int port, int in, int out) {
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pid_t pid = fork();
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if (pid == 0) {
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ext_in(addr, port);
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/* On établie ici une connexion bidirectionelle en se connectant à un
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* serveur distant ET en écoutant nous-même sur un port local en
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* attente d’un client. Cela nous donne donc deux connexions
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* matérialisées par deux socket, l’une qui est utilisée en lecture et
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* l’autre en écriture.
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*
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* Il pourrait suffir d’avoir une extremité qui écoute, et l’autre qui
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* se connecte, établissant ainsi une seule connexion qu’on
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* utiliserait en lecture/écriture, mais cela pose le problème de
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* savoir qui écoute et qui se connecte.
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*
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* De plus, si les deux tentent en parallèle de se connecter OU
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* d’accepter une connexion (mais de ne pas attendre que les deux
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* conditions soient vraies, et d’utiliser une seule socket en
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* lecture/écriture, la première disponible), se posent tout un tas de
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* problèmes de synchronisation si les deux extrémités du tunnel
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* essaient de se connecter en même temps par exemple.
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*/
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void ext_bidir(const char addr[], int port, int local_port, int local_r, int local_w) {
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/* First, let’s establish a full-duplex connection. */
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int server = setup_out(local_port);
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int peer_r; /* Future remote client socket to read from. */
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int peer_w = setup_in(addr, port);
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int client_connected = 0;
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int server_connected = 0;
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struct timeval one_sec = {.tv_sec=1, .tv_usec=0};
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struct timeval *timeout = &one_sec;
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fd_set set;
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while (!(client_connected && server_connected)) {
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if (!client_connected) {
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FD_ZERO(&set);
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FD_SET(server, &set);
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}
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select(server + 1, &set, NULL, NULL, timeout);
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if (FD_ISSET(server, &set)) {
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/* The server socket is readable, a peer is trying to
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* connect. */
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fputs("acceptation\n", stderr);
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peer_r = accept_client(server);
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FD_CLR(server, &set);
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client_connected = 1;
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fputs("Client connecté.\n", stderr);
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}
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else {
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/* Attempt to connect every second. */
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if (try_connect(peer_w, addr, port)) {
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timeout = NULL;
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server_connected = 1;
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fputs("Connecté au serveur.\n", stderr);
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}
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else {
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timeout->tv_sec = 1;
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timeout->tv_usec = 0;
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}
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}
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}
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else {
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ext_out(port);
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waitpid(pid, NULL, 0);
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fputs("Connexion bidirectionelle établie.\n", stderr);
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fd_set rfd;
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int nfds = peer_r > local_r ? peer_r : local_r;
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nfds++;
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char in_buf[1024];
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char out_buf[1024];
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while (1) {
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FD_ZERO(&rfd);
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FD_SET(peer_r, &rfd);
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FD_SET(local_r, &rfd);
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select(nfds, &rfd, NULL, NULL, NULL);
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if (FD_ISSET(peer_r, &rfd)) {
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/* Ready to read from client. */
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ssize_t n = read(peer_r, in_buf, sizeof in_buf);
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if (n < 0) {
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perror("read (from out)");
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exit(1);
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}
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if (write(local_w, in_buf, n) < 0) {
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perror("write (to local_out)");
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exit(1);
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}
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}
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if (FD_ISSET(local_r, &rfd)) {
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/* Ready to read from tun dev. */
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ssize_t n = read(local_r, out_buf, sizeof out_buf);
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if (n < 0) {
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perror("read (from local_in)");
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exit(1);
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}
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if (write(peer_w, out_buf, n) < 0) {
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perror("write (to in)");
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exit(1);
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}
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}
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}
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}
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@ -2,9 +2,18 @@
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#define EXTREMITE_H
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/* Sets up a tunnel exit on the specified PORT, returns a readable fd
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* representing it. */
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int ext_out(int port);
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/* Sets up a tunnel entrance connected to the exit at ADDR and PORT,
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* returns a writable fd representing it. */
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int ext_in(const char addr[], int port);
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void ext_bidir(const char addr[], int port, int in, int out);
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/* Establishes a full-duplex tunnel listening on LOCAL_PORT and
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* connected to ADDR and PORT. Copies data from local_r to the tunnel,
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* and data from the tunnel to local_w. */
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void ext_bidir(const char addr[], int port, int local_port, int local_r, int local_w);
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#endif
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@ -34,6 +34,7 @@ int tun_alloc(const char *dev) {
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int err = ioctl(fd, TUNSETIFF, (void *) &ifr);
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if(err < 0){
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perror("ioctl");
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exit(1);
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}
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@ -46,7 +47,15 @@ int copy(int src, int dest) {
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int n = 0;
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while (1) {
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n = read(src, buf, 1024);
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write(dest, buf, n);
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n = read(src, buf, sizeof buf);
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if (n < 0) {
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perror("copy");
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exit(1);
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}
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n = write(dest, buf, n);
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if (n < 0) {
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perror("copy");
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exit(1);
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}
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}
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}
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@ -68,7 +68,7 @@ int main(int argc, char *argv[argc]) {
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fprintf(stderr, "Erreur lors de l’exécution du script de configuration de l’interface.\n");
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return 1;
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}
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ext_bidir(outip, outport, tun, tun);
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ext_bidir(outip, outport, inport, tun, tun);
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return 0;
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}
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@ -1,6 +1,7 @@
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#include "iftun.h"
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#include <stdio.h>
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#include <unistd.h>
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int main(int argc, char *argv[argc]) {
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@ -8,6 +9,12 @@ int main(int argc, char *argv[argc]) {
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fprintf(stderr, "Utilisation : %s interface\n", argv[0]);
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return 1;
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}
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if (getuid() != 0) {
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fprintf(stderr, "%s doit être lancé en tant que superutilisateur.\n", argv[0]);
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return 1;
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}
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int tun = tun_alloc(argv[1]);
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fprintf(stderr, "Configurez l’interface puis appuyez sur <Entrée>... ");
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fflush(stderr);
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