1 files changed, 121 insertions, 0 deletions
diff --git a/src/rexmpp_socks.c b/src/rexmpp_socks.c
new file mode 100644
index 0000000..48046bb
--- /dev/null
+++ b/src/rexmpp_socks.c
@@ -0,0 +1,121 @@
+#include <memory.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <errno.h>
+#include <stdint.h>
+#include <arpa/inet.h>
+
+#include "rexmpp_socks.h"
+
+enum socks_err
+rexmpp_socks_proceed (rexmpp_socks_t *s)
+{
+  ssize_t ret;
+  if (s->io_state == REXMPP_SOCKS_WRITING) {
+    ssize_t ret = send(s->fd, s->buf + s->buf_sent,
+                        s->buf_len - s->buf_sent, 0);
+    if (ret > 0) {
+      s->buf_sent += ret;
+      if (s->buf_len == s->buf_sent) {
+        s->buf_len = 0;
+        s->io_state = REXMPP_SOCKS_READING;
+      }
+    } else if (errno == EAGAIN) {
+      return REXMPP_SOCKS_E_AGAIN;
+    } else {
+      return REXMPP_SOCKS_E_TCP;
+    }
+  } else if (s->io_state == REXMPP_SOCKS_READING) {
+    ret = recv(s->fd, s->buf + s->buf_len,
+               REXMPP_SOCKS_BUF_LEN - s->buf_len, 0);
+    if (ret > 0) {
+      s->buf_len += ret;
+      if (s->buf[0] != 5) {
+        return REXMPP_SOCKS_E_VERSION;
+      }
+      if (s->buf_len >= 2) {
+        s->socks_error = s->buf[1];
+      }
+      if (s->stage == REXMPP_SOCKS_AUTH) {
+        if (s->buf_len > 2) {
+          return REXMPP_SOCKS_E_REPLY;
+        }
+        if (s->buf_len == 2) {
+          if (s->socks_error != 0) {
+            return REXMPP_SOCKS_E_SOCKS;
+          }
+          /* It's okay to not authenticate, now we send a command. */
+          s->buf[0] = 5;      /* SOCKS version 5 */
+          s->buf[1] = 1;      /* Connect */
+          s->buf[2] = 0;      /* Reserved */
+          s->buf[3] = 3;      /* Domain name (todo: IP addresses) */
+          size_t len = strlen(s->host);
+          s->buf[4] = len;
+          memcpy(s->buf + 5, s->host, len);
+          uint16_t port = htons(s->port);
+          memcpy(s->buf + 5 + len, &port, 2);
+          s->buf_len = 7 + len;
+          s->buf_sent = 0;
+          s->stage = REXMPP_SOCKS_CMD;
+          s->io_state = REXMPP_SOCKS_WRITING;
+          return rexmpp_socks_proceed(s);
+        }
+      } else if (s->stage == REXMPP_SOCKS_CMD) {
+        if (s->buf_len >= 5) {
+          size_t full_len = 6;
+          if (s->buf[3] == 1) { /* IPv4 */
+            full_len += 4;
+          } else if (s->buf[3] == 3) { /* Domain name */
+            full_len += s->buf[4] + 1;
+          } else if (s->buf[3] == 4) { /* IPv6 */
+            full_len += 16;
+          } else {
+            return REXMPP_SOCKS_E_REPLY;
+          }
+          if (s->buf_len > full_len) {
+            return REXMPP_SOCKS_E_REPLY;
+          }
+          if (s->buf_len == full_len) {
+            if (s->socks_error != 0) {
+              return REXMPP_SOCKS_E_SOCKS;
+            }
+            /* We're done. */
+            s->stage = REXMPP_SOCKS_DONE;
+            return REXMPP_SOCKS_CONNECTED;
+          }
+        }
+      }
+    } else if (errno == EAGAIN) {
+      return REXMPP_SOCKS_E_AGAIN;
+    } else {
+      return REXMPP_SOCKS_E_TCP;
+    }
+  }
+  return REXMPP_SOCKS_E_AGAIN;
+}
+
+enum socks_err
+rexmpp_socks_init (rexmpp_socks_t *s,
+                   int fd,
+                   const char *host,
+                   uint16_t port)
+{
+  s->fd = fd;
+  s->host = host;
+  s->port = port;
+  s->socks_error = 0;
+
+  if (strlen(host) > 255) {
+    return REXMPP_SOCKS_E_HOST;
+  }
+
+  /* Request authentication. */
+  s->stage = REXMPP_SOCKS_AUTH;
+  s->io_state = REXMPP_SOCKS_WRITING;
+  s->buf[0] = 5;                /* SOCKS version 5 */
+  s->buf[1] = 1;                /* 1 supported method */
+  s->buf[2] = 0;                /* "no authentication required" */
+  s->buf_len = 3;
+  s->buf_sent = 0;
+  return rexmpp_socks_proceed(s);
+}