tor_multipath_voip/src/socks5.c

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#include "socks5.h"
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struct socks5_ctx {
struct client_handshake ch;
struct server_handshake sh;
struct client_request cr;
char cr_buffer[262];
struct server_reply sr;
};
void socks5_free_ctx(void* elem) {
struct socks5_ctx* ctx = elem;
free(ctx);
}
void create_socks5_dns_client(struct evt_core_ctx* ctx, char* proxy_host, char* proxy_port, char* addr, uint16_t port) {
int sock = create_tcp_client (proxy_host, proxy_port);
struct evt_core_fdinfo fdinfo;
struct evt_core_cat cat;
fdinfo.cat = &cat;
fdinfo.cat->name = "socks5-send-handshake";
fdinfo.fd = sock;
fdinfo.other = malloc(sizeof(struct socks5_ctx));
if (fdinfo.other == NULL) {
perror("malloc failed");
exit(EXIT_FAILURE);
}
fdinfo.free_other = socks5_free_ctx;
evt_core_add_fd (ctx, &fdinfo);
}
int socks5_handshake_syn(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
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struct client_handshake ch = {
.ver = 0x05,
.nmethods = 0x01,
.methods = {0x00}
};
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fdinfo->
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int size = sizeof(uint8_t) * (2 + ch.nmethods);
if (size != write(sock, &ch, size)) {
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perror("write failed on tcp socket in socks5");
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return -1;
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}
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return 0;
}
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int socks5_handshake_ack(int sock) {
struct client_handshake ch = {
.ver = 0x05,
.nmethods = 0x01,
.methods = {0x00}
};
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struct server_handshake sh = {0};
int err = read_entity(sock, &sh, sizeof(struct server_handshake));
if (err == -1) {
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perror("sock5 handshake failed read");
return -1;
}
if (ch.ver != sh.ver || sh.method != ch.methods[0]) {
fprintf(stderr, "Protocol error: client asks for ver=%d, method=%d and server answers with ver=%d, method=%d\n",
ch.ver, ch.methods[0], sh.ver, sh.method);
return -1;
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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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int res;
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struct server_reply sr = {0};
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res = read_entity(sock, &sr, sizeof(uint8_t) * 4);
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if (res == -1) goto read_error;
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switch(sr.atyp) {
case ATYP_IPV4:
if (read_entity(sock, sr.bind_addr.ipv4, sizeof(uint8_t) * 4) == -1)
goto read_error;
break;
case ATYP_DOMAINNAME:
if (read_entity(sock, &sr.bind_addr.dns.len, sizeof(uint8_t) * 4) == -1)
goto read_error;
if (read_entity(sock, sr.bind_addr.dns.str, sizeof(char) * sr.bind_addr.dns.len) == -1)
goto read_error;
break;
case ATYP_IPV6:
if (read_entity(sock, sr.bind_addr.ipv6, sizeof(uint8_t) * 16) == -1)
goto read_error;
break;
default:
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fprintf(stderr, "Unsupported ATYP in server reply\n");
return -128;
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}
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res = read_entity(sock, &sr.port, sizeof(uint16_t));
if (res == -1) {
perror("read_entity");
exit(EXIT_FAILURE);
}
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if (sr.rep < 0 || sr.rep > 0x08) {
fprintf(stderr, "Invalid reply field\n");
return -128;
}
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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);
return -sr.rep;
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read_error:
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fprintf(stderr, "Unable to read ATYP\n");
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];
size_t domainLength = strlen(addr);
if (domainLength > 255) {
fprintf(stderr, "domain is too long\n");
exit(EXIT_FAILURE);
}
struct client_request cr = { 0x05, CMD_CONNECT, 0x00, ATYP_DOMAINNAME, (uint8_t)domainLength, addr, htons(port) };
size_t written = 0;
fill_buffer(&written, buffer, &cr, 5*sizeof(uint8_t));
fill_buffer(&written, buffer, cr.dst_addr, cr.dst_addr_len*sizeof(char));
fill_buffer(&written, buffer, &cr.port, sizeof(uint16_t));
if (written != write(sock, buffer, written)) {
fprintf(stderr, "partial/failed write\n");
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return -1;
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}
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return 0;
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}
char* socks5_rep (enum socks5_rep rep) {
return rep_msg[rep];
}