udp tunnel 转udp 到 tcp

/* Wait for an incoming TCP connection. Once it arrives, listen for UDP on * the specified port, then send the UDP packets (with a length header) over * the TCP connection */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <errno.h> #include <signal.h> #include <sys/time.h> #include <sys/types.h> #include <unistd.h> #include <fcntl.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include "host2ip.h" #define UDPBUFFERSIZE 65536 #define TCPBUFFERSIZE (UDPBUFFERSIZE + 2) /* UDP packet + 2 (length field) */ #define SET_MAX(fd) do { if (max < (fd) + 1) { max = (fd) + 1; } } while (0) #if (SIZEOF_SHORT == 2) typedef unsigned short u_int16; #else #error Need a typedef for a 16-bit type #endif typedef unsigned char u_int8; struct out_packet { u_int16 length; char buf[UDPBUFFERSIZE]; }; struct relay { struct sockaddr_in udpaddr; struct sockaddr_in tcpaddr; u_int8 udp_ttl; int multicast_udp; int udp_send_sock; int udp_recv_sock; int tcp_listen_sock; int tcp_sock; char buf[TCPBUFFERSIZE]; char *buf_ptr, *packet_start; int packet_length; enum {uninitialized = 0, reading_length, reading_packet} state; }; static int debug = 0; /* * usage() * Print the program usage info, and exit. */ static void usage(char *progname) { fprintf(stderr, "Usage: %s -s TCP-port [-r] [-v] UDP-addr/UDP-port[/ttl]\n", progname); fprintf(stderr, " or %s -c TCP-addr[/TCP-port] [-r] [-v] UDP-addr/UDP-port[/ttl]\n", progname); fprintf(stderr, " -s: Server mode. Wait for TCP connections on the port.\n"); fprintf(stderr, " -c: Client mode. Connect to the given address.\n"); fprintf(stderr, " -r: RTP mode. Connect/listen on ports N and N+1 for both UDP and TCP.\n"); fprintf(stderr, " Port numbers must be even.\n"); fprintf(stderr, " -v: Verbose mode. Specify -v multiple times for increased verbosity.\n"); exit(2); } /* usage */ /* * parse_args() * Parse argv, and return parsed info in **relays, *relay_count, and * *is_server. On failure, exit. */ static void parse_args(int argc, char *argv[], struct relay **relays, int *relay_count, int *is_server) { int c; char *tcphostname, *tcpportstr, *udphostname, *udpportstr, *udpttlstr; struct in_addr tcpaddr, udpaddr; int tcpport, udpport, udpttl; int i; *is_server = -1; *relay_count = 1; debug = 0; tcphostname = NULL; tcpportstr = NULL; while ((c = getopt(argc, argv, "s:c:rvh")) != EOF) { switch (c) { case 's': if (*is_server != -1) { fprintf(stderr, "%s: Only one of -s and -c may be specified.\n", argv[0]); exit(2); } *is_server = 1; tcpportstr = optarg; break; case 'c': if (*is_server != -1) { fprintf(stderr, "%s: Only one of -s and -c may be specified.\n", argv[0]); exit(2); } *is_server = 0; tcphostname = optarg; break; case 'r': *relay_count = 2; break; case 'v': debug++; break; case 'h': case '?': default: usage(argv[0]); break; } } if (*is_server == -1) { fprintf(stderr, "%s: You must specify one of -s and -c.\n", argv[0]); exit(2); } if (argc <= optind) { usage(argv[0]); } udphostname = strtok(argv[optind], ":/ "); udpportstr = strtok(NULL, ":/ "); if (udpportstr == NULL) { usage(argv[0]); } udpttlstr = strtok(NULL, ":/ "); if (!*is_server) { tcphostname = strtok(tcphostname, ":/ "); tcpportstr = strtok(NULL, ":/ "); } else { tcphostname = NULL; } errno = 0; udpport = strtol(udpportstr, NULL, 0); if (errno || udpport <= 0 || udpport >= 65536) { fprintf(stderr, "%s: invalid port number\n", udpportstr); exit(2); } if (udpttlstr != NULL) { errno = 0; udpttl = strtol(udpttlstr, NULL, 0); if (errno || udpttl < 0 || udpttl >= 256) { fprintf(stderr, "%s: invalid TTL\n", udpttlstr); exit(2); } } else { udpttl = 1; } if (tcpportstr != NULL) { errno = 0; tcpport = strtol(tcpportstr, NULL, 0); if (errno || tcpport <= 0 || tcpport >= 65536) { fprintf(stderr, "%s: invalid port number\n", tcpportstr); exit(2); } } else { tcpport = udpport; } if (*relay_count == 2 && (tcpport % 2 != 0 || udpport % 2 != 0)) { fprintf(stderr, "Port numbers must be even when using RTP mode.\n"); exit(2); } udpaddr = host2ip(udphostname); if (udpaddr.s_addr == INADDR_ANY) { fprintf(stderr, "%s: UDP host unknown\n", udphostname); exit(2); } if (*is_server) { tcpaddr.s_addr = INADDR_ANY; } else { tcpaddr = host2ip(tcphostname); if (tcpaddr.s_addr == INADDR_ANY) { fprintf(stderr, "%s: TCP host unknown\n", tcphostname); exit(2); } } *relays = (struct relay *) calloc(*relay_count, sizeof(struct relay)); if (relays == NULL) { perror("Error allocating relay structure"); exit(1); } for (i = 0; i < *relay_count; i++) { (*relays)[i].udpaddr.sin_addr = udpaddr; (*relays)[i].udpaddr.sin_port = htons(udpport + i); (*relays)[i].udpaddr.sin_family = AF_INET; (*relays)[i].udp_ttl = udpttl; (*relays)[i].multicast_udp = IN_MULTICAST(htons(udpaddr.s_addr)); (*relays)[i].tcpaddr.sin_addr = tcpaddr; (*relays)[i].tcpaddr.sin_port = htons(tcpport + i); (*relays)[i].tcpaddr.sin_family = AF_INET; } } /* parse_args */ /* setup_udp_recv() * Set up the UDP receiving socket for the specified relay. * Exit if anything goes wrong. */ static void setup_udp_recv(struct relay *relay) { int opt; struct sockaddr_in udp_recv_addr; if ((relay->udp_recv_sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0) { perror("setup_udp_recv: socket"); exit(1); } /* Set "reuseaddr" (and "reuseport", if it exists) */ opt = 1; if (setsockopt(relay->udp_recv_sock, SOL_SOCKET, SO_REUSEADDR, (void *)&opt, sizeof(opt)) < 0) { perror("setup_udp_recv: setsockopt(SO_REUSEADDR)"); exit(1); } #ifdef SO_REUSEPORT opt = 1; if (setsockopt(relay->udp_recv_sock, SOL_SOCKET, SO_REUSEPORT, (void *)&opt, sizeof(opt)) < 0) { perror("setup_udp_recv: setsockopt(SO_REUSEPORT)"); exit(1); } #endif if (relay->multicast_udp) { #ifdef IP_ADD_MEMBERSHIP struct ip_mreq mreq; /* multicast group */ mreq.imr_multiaddr = relay->udpaddr.sin_addr; mreq.imr_interface.s_addr = INADDR_ANY; if (setsockopt(relay->udp_recv_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (void *)&mreq, sizeof(mreq)) < 0) { perror("setup_udp_recv: setsockopt(IP_ADD_MEMBERSHIP)"); exit(1); } #else fprintf(stderr, "Multicast addresses not supported\n"); exit(1); #endif } memcpy(&udp_recv_addr, &(relay->udpaddr), sizeof(struct sockaddr_in)); if (!(relay->multicast_udp)) { /* XXX: some platforms don't allow you to bind to a multicast addr; these need to bind recv_addr to INADDR_ANY regardless? */ udp_recv_addr.sin_addr.s_addr = INADDR_ANY; } if (bind(relay->udp_recv_sock, (struct sockaddr *)&udp_recv_addr, sizeof(udp_recv_addr)) < 0) { perror("setup_udp_recv: bind"); exit(1); } return; } /* setup_udp_recv */ /* setup_udp_send() * Set up the UDP sending socket for the specified relay. * Exit if anything goes wrong. */ static void setup_udp_send(struct relay *relay) { /* Create UDP socket. */ if ((relay->udp_send_sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0) { perror("setup_udp_send: socket"); exit(1); } if (connect(relay->udp_send_sock, (struct sockaddr *) &(relay->udpaddr), sizeof(relay->udpaddr)) < 0) { perror("setup_udp_send: connect"); exit(1); } if (IN_MULTICAST(htonl(relay->udpaddr.sin_addr.s_addr))) { #ifdef IP_MULTICAST_LOOP u_int8 loop = 0; if (setsockopt