tor_multipath_voip/src/socks5.c
2019-09-15 16:14:26 +02:00

322 lines
11 KiB
C

#include "socks5.h"
void socks5_free_ctx(void* elem) {
struct socks5_ctx* ctx = elem;
free(ctx->addr);
free(ctx);
}
void socks5_create_dns_client(struct evt_core_ctx* ctx, char* proxy_host, char* proxy_port, char* addr, uint16_t port) {
struct evt_core_fdinfo fdinfo;
struct evt_core_cat cat;
struct socks5_ctx* s5ctx;
struct evt_core_fdinfo* reg_fdinfo;
char url[1024];
// 0. Compute domain length and enforce an upper bound on its size
size_t domainLength = strlen(addr);
if (domainLength > 255) {
fprintf(stderr, "domain is too long\n");
exit(EXIT_FAILURE);
}
// 1. Open connection
int sock = create_tcp_client (proxy_host, proxy_port);
if (sock < 0) {
fprintf(stderr, "Unable to connect to proxy %s:%s\n", proxy_host, proxy_port);
exit(EXIT_FAILURE);
}
// 2. Create fdinfo
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);
}
memset(fdinfo.other, 0, sizeof(struct socks5_ctx));
fdinfo.free_other = socks5_free_ctx;
sprintf(url, "socks5:send-hs:%s:%d", addr, port);
fdinfo.url = url;
// 3. Fill socks5_ctx structures
s5ctx = fdinfo.other;
s5ctx->port = port;
s5ctx->addr = strdup(addr);
// 3.1 Client handshake to send
s5ctx->ch.ver = VER_SOCKS5;
s5ctx->ch.nmethods = 0x01;
s5ctx->ch.methods[0] = METHOD_NOAUTH;
s5ctx->ch_size = sizeof(uint8_t) * (2 + s5ctx->ch.nmethods);
// 3.2 Client request to send
s5ctx->cr.ver = VER_SOCKS5;
s5ctx->cr.cmd = CMD_CONNECT;
s5ctx->cr.rsv = 0x00;
s5ctx->cr.atyp = ATYP_DOMAINNAME;
s5ctx->cr.dst_addr_len = domainLength;
s5ctx->cr.dst_addr = addr;
s5ctx->cr.port = htons(port);
// 3.3 Generate client request buffer
s5ctx->cr_size = 0;
fill_buffer(&s5ctx->cr_size, s5ctx->cr_buffer, &s5ctx->cr, 5*sizeof(uint8_t));
fill_buffer(&s5ctx->cr_size, s5ctx->cr_buffer, s5ctx->cr.dst_addr, s5ctx->cr.dst_addr_len*sizeof(char));
fill_buffer(&s5ctx->cr_size, s5ctx->cr_buffer, &s5ctx->cr.port, sizeof(uint16_t));
reg_fdinfo = evt_core_add_fd (ctx, &fdinfo);
}
int on_socks5_send_handshake(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
struct socks5_ctx* s5ctx = fdinfo->other;
size_t written = write(fdinfo->fd, (char*)&s5ctx->ch + s5ctx->ch_cursor, s5ctx->ch_size - s5ctx->ch_cursor);
if (written == -1 && errno == EAGAIN) return 1;
if (written < 0) {
perror("write failed on tcp socket in socks5");
evt_core_mv_fd2(ctx, fdinfo, "socks5-failed");
return 1;
}
s5ctx->ch_cursor += written;
if (s5ctx->ch_cursor < s5ctx->ch_size) return 0;
evt_core_mv_fd2(ctx, fdinfo, "socks5-recv-handshake");
return 1;
}
int on_socks5_recv_handshake(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
struct socks5_ctx* s5ctx = fdinfo->other;
int readn = 0;
readn = read(fdinfo->fd, (char*)&s5ctx->sh + s5ctx->sh_cursor, sizeof(s5ctx->sh) - s5ctx->sh_cursor);
if (readn == -1 && errno == EAGAIN) return 1;
if (readn < 0) {
perror("sock5 handshake failed read");
evt_core_mv_fd2(ctx, fdinfo, "socks5-failed");
return 1;
}
s5ctx->sh_cursor += readn;
if (s5ctx->sh_cursor < sizeof(s5ctx->sh)) return 0;
if (s5ctx->ch.ver != s5ctx->sh.ver || s5ctx->sh.method != s5ctx->ch.methods[0]) {
fprintf(stderr, "Protocol error: client asks for ver=%d, method=%d and server answers with ver=%d, method=%d\n",
s5ctx->ch.ver, s5ctx->ch.methods[0], s5ctx->sh.ver, s5ctx->sh.method);
evt_core_mv_fd2(ctx, fdinfo, "socks5-failed");
return 1;
}
printf("[socks5_server_handshake] fd=%d, ver=%d, method=%d\n", fdinfo->fd, s5ctx->sh.ver, s5ctx->sh.method);
evt_core_mv_fd2(ctx, fdinfo, "socks5-send-client-req");
return 1;
}
int on_socks5_send_client_req(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
struct socks5_ctx* s5ctx = fdinfo->other;
int written = 0;
written = write(fdinfo->fd, (char*)s5ctx->cr_buffer + s5ctx->cr_cursor, s5ctx->cr_size - s5ctx->cr_cursor);
if (written == -1 && errno == EAGAIN) return 1;
if (written < 0) {
fprintf(stderr, "socks5 send client request failed\n");
evt_core_mv_fd2 (ctx, fdinfo, "socks5-failed");
return 1;
}
s5ctx->cr_cursor += written;
printf("[socks5_server_send_client_req] sent %ld/%ld\n", s5ctx->cr_cursor, s5ctx->cr_size);
if (s5ctx->cr_cursor < s5ctx->cr_size) return 0; // Trigger loop to trigger EAGAIN.
evt_core_mv_fd2 (ctx, fdinfo, "socks5-recv-server-reply");
return 1;
}
int socks5_server_reply_atyp_ipv4(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
struct socks5_ctx* s5ctx = fdinfo->other;
size_t fixed_headers_size = (char*)&s5ctx->sr.bind_addr.ipv4 - (char*)&s5ctx->sr;
size_t host_size = sizeof(s5ctx->sr.bind_addr.ipv4);
uint64_t relative_cursor = (s5ctx->sr_cursor - fixed_headers_size);
int nread = 0;
nread = read(fdinfo->fd,
(char*)s5ctx->sr.bind_addr.ipv4 + relative_cursor,
host_size - relative_cursor);
if (nread == -1 && errno == EAGAIN) return 1;
if (nread < 0) {
perror("write failed on tcp socket in socks5");
evt_core_mv_fd2(ctx, fdinfo, "socks5-failed");
return 1;
}
s5ctx->sr_cursor += nread;
if (s5ctx->sr_cursor < fixed_headers_size + host_size) return 0;
s5ctx->sr_host_read = 1;
return 0;
}
int socks5_server_reply_atyp_ipv6(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
struct socks5_ctx* s5ctx = fdinfo->other;
size_t fixed_headers_size = (char*)&s5ctx->sr.bind_addr.ipv6 - (char*)&s5ctx->sr;
size_t host_size = sizeof(s5ctx->sr.bind_addr.ipv6);
uint64_t relative_cursor = (s5ctx->sr_cursor - fixed_headers_size);
int nread = 0;
nread = read(fdinfo->fd,
(char*)s5ctx->sr.bind_addr.ipv6 + relative_cursor,
host_size - relative_cursor);
if (nread == -1 && errno == EAGAIN) return 1;
if (nread < 0) {
perror("write failed on tcp socket in socks5");
evt_core_mv_fd2(ctx, fdinfo, "socks5-failed");
return 1;
}
s5ctx->sr_cursor += nread;
if (s5ctx->sr_cursor < fixed_headers_size + host_size) return 0;
s5ctx->sr_host_read = 1;
return 0;
}
int socks5_server_reply_atyp_dn(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
struct socks5_ctx* s5ctx = fdinfo->other;
size_t fixed_headers_size = (char*)&s5ctx->sr.bind_addr.ipv6 - (char*)&s5ctx->sr;
size_t dn_size_size = sizeof(s5ctx->sr.bind_addr.dns.len);
uint64_t relative_cursor = 0;
int nread = 0;
if (s5ctx->sr_cursor < fixed_headers_size + dn_size_size) {
relative_cursor = (s5ctx->sr_cursor - fixed_headers_size);
nread = read(fdinfo->fd, (char*)&s5ctx->sr.bind_addr.dns.len + relative_cursor, dn_size_size - relative_cursor);
if (nread == -1 && errno == EAGAIN) return 1;
if (nread < 0) {
perror("write failed on tcp socket in socks5");
evt_core_mv_fd2(ctx, fdinfo, "socks5-failed");
return 1;
}
s5ctx->sr_cursor += nread;
return 0;
}
relative_cursor = s5ctx->sr_cursor - fixed_headers_size - sizeof(s5ctx->sr.bind_addr.dns.len);
nread = read(fdinfo->fd, (char*)&s5ctx->sr.bind_addr.dns.str + relative_cursor, s5ctx->sr.bind_addr.dns.len - relative_cursor);
if (nread == -1 && errno == EAGAIN) return 1;
if (nread < 0) {
perror("write failed on tcp socket in socks5");
evt_core_mv_fd2(ctx, fdinfo, "socks5-failed");
return 1;
}
s5ctx->sr_cursor += nread;
if (s5ctx->sr_cursor < fixed_headers_size + dn_size_size + s5ctx->sr.bind_addr.dns.len) return 0;
s5ctx->sr_host_read = 1;
return 0;
}
size_t socks5_server_reply_size(struct server_reply* sr) {
size_t fixed_headers_size = (char*)&sr->bind_addr - (char*)sr;
size_t fixed_tail_size = (char*)(sr + 1) - (char*)&sr->port;
size_t host_size = 0;
if (sr->atyp == ATYP_IPV4) {
host_size = sizeof(sr->bind_addr.ipv4);
} else if (sr->atyp == ATYP_IPV6) {
host_size = sizeof(sr->bind_addr.ipv6);
} else if (sr->atyp == ATYP_DOMAINNAME) {
host_size = sizeof(sr->bind_addr.dns.len) + sr->bind_addr.dns.len;
} else {
fprintf(stderr, "Unsupported ATYP for SOCK5\n");
exit(EXIT_FAILURE);
}
return fixed_headers_size + host_size + fixed_tail_size;
}
int on_socks5_recv_server_reply(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
struct socks5_ctx* s5ctx = fdinfo->other;
int readn = 0;
size_t fixed_headers_size = (char*)&s5ctx->sr.bind_addr - (char*)&s5ctx->sr;
// Read headers
if (s5ctx->sr_cursor < fixed_headers_size) {
printf(" [socks5] read headers\n");
readn = read(fdinfo->fd, (char*)&s5ctx->sr + s5ctx->sr_cursor, fixed_headers_size - s5ctx->sr_cursor);
if (readn == -1 && errno == EAGAIN) return 1;
if (readn < 0) goto move_to_failed;
s5ctx->sr_cursor += readn;
return 0; // Needed as we might have not read enough bytes and free us from writing a loop
}
// Read host
if (!s5ctx->sr_host_read) {
printf(" [socks5] read host\n");
if (s5ctx->sr.atyp == ATYP_IPV4) return socks5_server_reply_atyp_ipv4(ctx, fdinfo);
else if (s5ctx->sr.atyp == ATYP_IPV6) return socks5_server_reply_atyp_ipv6(ctx, fdinfo);
else if (s5ctx->sr.atyp == ATYP_DOMAINNAME) return socks5_server_reply_atyp_dn(ctx, fdinfo);
else goto move_to_failed;
}
// Read port
size_t final_size = socks5_server_reply_size(&s5ctx->sr);
if (s5ctx->sr_cursor < final_size) {
printf(" [socks5] read port\n");
size_t relative_cursor = s5ctx->sr_cursor - (final_size - sizeof(s5ctx->sr.port));
readn = read(fdinfo->fd, (char*)&s5ctx->sr.port + relative_cursor, sizeof(s5ctx->sr.port) - relative_cursor);
if (readn == -1 && errno == EAGAIN) return 1;
if (readn < 0) goto move_to_failed;
s5ctx->sr_cursor += readn;
return 0; // Needed as we might have not read enough bytes and free us from writing a loop
}
// Do some checks
if (s5ctx->sr.rep > 0x08) goto move_to_failed;
printf("[socks5_server_reply] fd=%d, ver=%d, rep=%s, atyp=%d, port=%d\n", fdinfo->fd, s5ctx->sr.ver, rep_msg[s5ctx->sr.rep], s5ctx->sr.atyp, s5ctx->sr.port);
if (s5ctx->sr.rep != SOCKS5_REP_SUCCESS) goto move_to_failed;
evt_core_mv_fd2 (ctx, fdinfo, "socks5-success");
return 1;
move_to_failed:
evt_core_mv_fd2 (ctx, fdinfo, "socks5-failed");
return 1;
}
int on_socks5_err(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
evt_core_mv_fd2 (ctx, fdinfo, "socks5-failed");
return 1;
}
void socks5_init(struct evt_core_ctx* ctx) {
struct evt_core_cat template = {0};
template.cb = on_socks5_send_handshake;
template.err_cb = on_socks5_err;
template.name = "socks5-send-handshake";
template.flags = EPOLLOUT | EPOLLET;
evt_core_add_cat (ctx, &template);
template.cb = on_socks5_recv_handshake;
template.err_cb = on_socks5_err;
template.name = "socks5-recv-handshake";
template.flags = EPOLLIN | EPOLLET;
evt_core_add_cat (ctx, &template);
template.cb = on_socks5_send_client_req;
template.err_cb = on_socks5_err;
template.name = "socks5-send-client-req";
template.flags = EPOLLOUT | EPOLLET;
evt_core_add_cat(ctx, &template);
template.cb = on_socks5_recv_server_reply;
template.err_cb = on_socks5_err;
template.name = "socks5-recv-server-reply";
template.flags = EPOLLIN | EPOLLET;
evt_core_add_cat(ctx, &template);
}
char* socks5_rep (enum socks5_rep rep) {
return rep_msg[rep];
}