86 lines
2.8 KiB
C
86 lines
2.8 KiB
C
#include "socks5.h"
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int socks5_handshake(int sock) {
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struct client_handshake ch = {
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.ver = 0x05,
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.nmethods = 0x01,
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.methods = {0x00}
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};
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int size = sizeof(uint8_t) * (2 + ch.nmethods);
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if (size != write(sock, &ch, size)) {
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fprintf(stderr, "partial/failed write\n");
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return -1;
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}
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struct server_handshake sh = {0};
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int err = read_entity(sock, &sh, sizeof(struct server_handshake));
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if (err == -1) {
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perror("sock5 handshake failed read");
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return -1;
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}
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if (ch.ver != sh.ver || sh.method != ch.methods[0]) {
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fprintf(stderr, "Protocol error: client asks for ver=%d, method=%d and server answers with ver=%d, method=%d\n",
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ch.ver, ch.methods[0], sh.ver, sh.method);
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return -1;
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}
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printf("[server_handshake] ver=%d, method=%d\n", sh.ver, sh.method);
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return 0;
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}
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int socks5_reply(int sock) {
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struct server_reply sr = {0};
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read_entity(sock, &sr, sizeof(uint8_t) * 4);
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switch(sr.atyp) {
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case ATYP_IPV4:
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if (read_entity(sock, sr.bind_addr.ipv4, sizeof(uint8_t) * 4) == -1)
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goto read_error;
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break;
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case ATYP_DOMAINNAME:
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if (read_entity(sock, &sr.bind_addr.dns.len, sizeof(uint8_t) * 4) == -1)
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goto read_error;
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if (read_entity(sock, sr.bind_addr.dns.str, sizeof(char) * sr.bind_addr.dns.len) == -1)
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goto read_error;
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break;
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case ATYP_IPV6:
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if (read_entity(sock, sr.bind_addr.ipv6, sizeof(uint8_t) * 16) == -1)
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goto read_error;
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break;
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default:
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fprintf(stderr, "Unsupported ATYP in server reply\n");
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return -128;
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}
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read_entity(sock, &sr.port, sizeof(uint16_t));
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if (sr.rep < 0 || sr.rep > 0x08) {
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fprintf(stderr, "Invalid reply field\n");
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return -128;
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}
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printf("[server_reply] ver=%d, rep=%s, atyp=%d, port=%d\n", sr.ver, rep_msg[sr.rep], sr.atyp, sr.port);
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return -sr.rep;
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read_error:
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fprintf(stderr, "Unable to read ATYP\n");
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return -128;
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}
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int socks5_connect_dns(int sock, char* addr, uint16_t port) {
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char buffer[262];
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size_t domainLength = strlen(addr);
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if (domainLength > 255) {
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fprintf(stderr, "domain is too long\n");
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exit(EXIT_FAILURE);
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}
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struct client_request cr = { 0x05, CMD_CONNECT, 0x00, ATYP_DOMAINNAME, (uint8_t)domainLength, addr, htons(port) };
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size_t written = 0;
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fill_buffer(&written, buffer, &cr, 5*sizeof(uint8_t));
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fill_buffer(&written, buffer, cr.dst_addr, cr.dst_addr_len*sizeof(char));
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fill_buffer(&written, buffer, &cr.port, sizeof(uint16_t));
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if (written != write(sock, buffer, written)) {
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fprintf(stderr, "partial/failed write\n");
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return -1;
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}
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}
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