--- /dev/null
+/*\r
+ * SSH port forwarding.\r
+ */\r
+\r
+#include <stdio.h>\r
+#include <stdlib.h>\r
+\r
+#include "putty.h"\r
+#include "ssh.h"\r
+\r
+#ifndef FALSE\r
+#define FALSE 0\r
+#endif\r
+#ifndef TRUE\r
+#define TRUE 1\r
+#endif\r
+\r
+struct PFwdPrivate {\r
+ const struct plug_function_table *fn;\r
+ /* the above variable absolutely *must* be the first in this structure */\r
+ void *c; /* (channel) data used by ssh.c */\r
+ void *backhandle; /* instance of SSH backend itself */\r
+ /* Note that backhandle need not be filled in if c is non-NULL */\r
+ Socket s;\r
+ int throttled, throttle_override;\r
+ int ready;\r
+ /*\r
+ * `dynamic' does double duty. It's set to 0 for an ordinary\r
+ * forwarded port, and nonzero for SOCKS-style dynamic port\r
+ * forwarding; but it also represents the state of the SOCKS\r
+ * exchange.\r
+ */\r
+ int dynamic;\r
+ /*\r
+ * `hostname' and `port' are the real hostname and port, once\r
+ * we know what we're connecting to; they're unused for this\r
+ * purpose while conducting a local SOCKS exchange, which means\r
+ * we can also use them as a buffer and pointer for reading\r
+ * data from the SOCKS client.\r
+ */\r
+ char hostname[256+8];\r
+ int port;\r
+ /*\r
+ * When doing dynamic port forwarding, we can receive\r
+ * connection data before we are actually able to send it; so\r
+ * we may have to temporarily hold some in a dynamically\r
+ * allocated buffer here.\r
+ */\r
+ void *buffer;\r
+ int buflen;\r
+};\r
+\r
+static void pfd_log(Plug plug, int type, SockAddr addr, int port,\r
+ const char *error_msg, int error_code)\r
+{\r
+ /* we have to dump these since we have no interface to logging.c */\r
+}\r
+\r
+static int pfd_closing(Plug plug, const char *error_msg, int error_code,\r
+ int calling_back)\r
+{\r
+ struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;\r
+\r
+ /*\r
+ * We have no way to communicate down the forwarded connection,\r
+ * so if an error occurred on the socket, we just ignore it\r
+ * and treat it like a proper close.\r
+ */\r
+ if (pr->c)\r
+ sshfwd_close(pr->c);\r
+ pfd_close(pr->s);\r
+ return 1;\r
+}\r
+\r
+static int pfd_receive(Plug plug, int urgent, char *data, int len)\r
+{\r
+ struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;\r
+ if (pr->dynamic) {\r
+ while (len--) {\r
+ /*\r
+ * Throughout SOCKS negotiation, "hostname" is re-used as a\r
+ * random protocol buffer with "port" storing the length.\r
+ */ \r
+ if (pr->port >= lenof(pr->hostname)) {\r
+ /* Request too long. */\r
+ if ((pr->dynamic >> 12) == 4) {\r
+ /* Send back a SOCKS 4 error before closing. */\r
+ char data[8];\r
+ memset(data, 0, sizeof(data));\r
+ data[1] = 91; /* generic `request rejected' */\r
+ sk_write(pr->s, data, 8);\r
+ }\r
+ pfd_close(pr->s);\r
+ return 1;\r
+ }\r
+ pr->hostname[pr->port++] = *data++;\r
+\r
+ /*\r
+ * Now check what's in the buffer to see if it's a\r
+ * valid and complete message in the SOCKS exchange.\r
+ */\r
+ if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 4) &&\r
+ pr->hostname[0] == 4) {\r
+ /*\r
+ * SOCKS 4.\r
+ */\r
+ if (pr->dynamic == 1)\r
+ pr->dynamic = 0x4000;\r
+ if (pr->port < 2) continue;/* don't have command code yet */\r
+ if (pr->hostname[1] != 1) {\r
+ /* Not CONNECT. */\r
+ /* Send back a SOCKS 4 error before closing. */\r
+ char data[8];\r
+ memset(data, 0, sizeof(data));\r
+ data[1] = 91; /* generic `request rejected' */\r
+ sk_write(pr->s, data, 8);\r
+ pfd_close(pr->s);\r
+ return 1;\r
+ }\r
+ if (pr->port <= 8) continue; /* haven't started user/hostname */\r
+ if (pr->hostname[pr->port-1] != 0)\r
+ continue; /* haven't _finished_ user/hostname */\r
+ /*\r
+ * Now we have a full SOCKS 4 request. Check it to\r
+ * see if it's a SOCKS 4A request.\r
+ */\r
+ if (pr->hostname[4] == 0 && pr->hostname[5] == 0 &&\r
+ pr->hostname[6] == 0 && pr->hostname[7] != 0) {\r
+ /*\r
+ * It's SOCKS 4A. So if we haven't yet\r
+ * collected the host name, we should continue\r
+ * waiting for data in order to do so; if we\r
+ * have, we can go ahead.\r
+ */\r
+ int len;\r
+ if (pr->dynamic == 0x4000) {\r
+ pr->dynamic = 0x4001;\r
+ pr->port = 8; /* reset buffer to overwrite name */\r
+ continue;\r
+ }\r
+ pr->hostname[0] = 0; /* reply version code */\r
+ pr->hostname[1] = 90; /* request granted */\r
+ sk_write(pr->s, pr->hostname, 8);\r
+ len= pr->port - 8;\r
+ pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2);\r
+ memmove(pr->hostname, pr->hostname + 8, len);\r
+ goto connect;\r
+ } else {\r
+ /*\r
+ * It's SOCKS 4, which means we should format\r
+ * the IP address into the hostname string and\r
+ * then just go.\r
+ */\r
+ pr->hostname[0] = 0; /* reply version code */\r
+ pr->hostname[1] = 90; /* request granted */\r
+ sk_write(pr->s, pr->hostname, 8);\r
+ pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2);\r
+ sprintf(pr->hostname, "%d.%d.%d.%d",\r
+ (unsigned char)pr->hostname[4],\r
+ (unsigned char)pr->hostname[5],\r
+ (unsigned char)pr->hostname[6],\r
+ (unsigned char)pr->hostname[7]);\r
+ goto connect;\r
+ }\r
+ }\r
+\r
+ if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 5) &&\r
+ pr->hostname[0] == 5) {\r
+ /*\r
+ * SOCKS 5.\r
+ */\r
+ if (pr->dynamic == 1)\r
+ pr->dynamic = 0x5000;\r
+\r
+ if (pr->dynamic == 0x5000) {\r
+ int i, method;\r
+ char data[2];\r
+ /*\r
+ * We're receiving a set of method identifiers.\r
+ */\r
+ if (pr->port < 2) continue;/* no method count yet */\r
+ if (pr->port < 2 + (unsigned char)pr->hostname[1])\r
+ continue; /* no methods yet */\r
+ method = 0xFF; /* invalid */\r
+ for (i = 0; i < (unsigned char)pr->hostname[1]; i++)\r
+ if (pr->hostname[2+i] == 0) {\r
+ method = 0;/* no auth */\r
+ break;\r
+ }\r
+ data[0] = 5;\r
+ data[1] = method;\r
+ sk_write(pr->s, data, 2);\r
+ pr->dynamic = 0x5001;\r
+ pr->port = 0; /* re-empty the buffer */\r
+ continue;\r
+ }\r
+\r
+ if (pr->dynamic == 0x5001) {\r
+ /*\r
+ * We're receiving a SOCKS request.\r
+ */\r
+ unsigned char reply[10]; /* SOCKS5 atyp=1 reply */\r
+ int atype, alen = 0;\r
+\r
+ /*\r
+ * Pre-fill reply packet.\r
+ * In all cases, we set BND.{HOST,ADDR} to 0.0.0.0:0\r
+ * (atyp=1) in the reply; if we succeed, we don't know\r
+ * the right answers, and if we fail, they should be\r
+ * ignored.\r
+ */\r
+ memset(reply, 0, lenof(reply));\r
+ reply[0] = 5; /* VER */\r
+ reply[3] = 1; /* ATYP = 1 (IPv4, 0.0.0.0:0) */\r
+\r
+ if (pr->port < 6) continue;\r
+ atype = (unsigned char)pr->hostname[3];\r
+ if (atype == 1) /* IPv4 address */\r
+ alen = 4;\r
+ if (atype == 4) /* IPv6 address */\r
+ alen = 16;\r
+ if (atype == 3) /* domain name has leading length */\r
+ alen = 1 + (unsigned char)pr->hostname[4];\r
+ if (pr->port < 6 + alen) continue;\r
+ if (pr->hostname[1] != 1 || pr->hostname[2] != 0) {\r
+ /* Not CONNECT or reserved field nonzero - error */\r
+ reply[1] = 1; /* generic failure */\r
+ sk_write(pr->s, (char *) reply, lenof(reply));\r
+ pfd_close(pr->s);\r
+ return 1;\r
+ }\r
+ /*\r
+ * Now we have a viable connect request. Switch\r
+ * on atype.\r
+ */\r
+ pr->port = GET_16BIT_MSB_FIRST(pr->hostname+4+alen);\r
+ if (atype == 1) {\r
+ /* REP=0 (success) already */\r
+ sk_write(pr->s, (char *) reply, lenof(reply));\r
+ sprintf(pr->hostname, "%d.%d.%d.%d",\r
+ (unsigned char)pr->hostname[4],\r
+ (unsigned char)pr->hostname[5],\r
+ (unsigned char)pr->hostname[6],\r
+ (unsigned char)pr->hostname[7]);\r
+ goto connect;\r
+ } else if (atype == 3) {\r
+ /* REP=0 (success) already */\r
+ sk_write(pr->s, (char *) reply, lenof(reply));\r
+ memmove(pr->hostname, pr->hostname + 5, alen-1);\r
+ pr->hostname[alen-1] = '\0';\r
+ goto connect;\r
+ } else {\r
+ /*\r
+ * Unknown address type. (FIXME: support IPv6!)\r
+ */\r
+ reply[1] = 8; /* atype not supported */\r
+ sk_write(pr->s, (char *) reply, lenof(reply));\r
+ pfd_close(pr->s);\r
+ return 1;\r
+ }\r
+ }\r
+ }\r
+\r
+ /*\r
+ * If we get here without either having done `continue'\r
+ * or `goto connect', it must be because there is no\r
+ * sensible interpretation of what's in our buffer. So\r
+ * close the connection rudely.\r
+ */\r
+ pfd_close(pr->s);\r
+ return 1;\r
+ }\r
+ return 1;\r
+\r
+ /*\r
+ * We come here when we're ready to make an actual\r
+ * connection.\r
+ */\r
+ connect:\r
+\r
+ /*\r
+ * Freeze the socket until the SSH server confirms the\r
+ * connection.\r
+ */\r
+ sk_set_frozen(pr->s, 1);\r
+\r
+ pr->c = new_sock_channel(pr->backhandle, pr->s);\r
+ if (pr->c == NULL) {\r
+ pfd_close(pr->s);\r
+ return 1;\r
+ } else {\r
+ /* asks to forward to the specified host/port for this */\r
+ ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");\r
+ }\r
+ pr->dynamic = 0;\r
+\r
+ /*\r
+ * If there's any data remaining in our current buffer,\r
+ * save it to be sent on pfd_confirm().\r
+ */\r
+ if (len > 0) {\r
+ pr->buffer = snewn(len, char);\r
+ memcpy(pr->buffer, data, len);\r
+ pr->buflen = len;\r
+ }\r
+ }\r
+ if (pr->ready) {\r
+ if (sshfwd_write(pr->c, data, len) > 0) {\r
+ pr->throttled = 1;\r
+ sk_set_frozen(pr->s, 1);\r
+ }\r
+ }\r
+ return 1;\r
+}\r
+\r
+static void pfd_sent(Plug plug, int bufsize)\r
+{\r
+ struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;\r
+\r
+ if (pr->c)\r
+ sshfwd_unthrottle(pr->c, bufsize);\r
+}\r
+\r
+/*\r
+ * Called when receiving a PORT OPEN from the server\r
+ */\r
+const char *pfd_newconnect(Socket *s, char *hostname, int port,\r
+ void *c, const Config *cfg, int addressfamily)\r
+{\r
+ static const struct plug_function_table fn_table = {\r
+ pfd_log,\r
+ pfd_closing,\r
+ pfd_receive,\r
+ pfd_sent,\r
+ NULL\r
+ };\r
+\r
+ SockAddr addr;\r
+ const char *err;\r
+ char *dummy_realhost;\r
+ struct PFwdPrivate *pr;\r
+\r
+ /*\r
+ * Try to find host.\r
+ */\r
+ addr = name_lookup(hostname, port, &dummy_realhost, cfg, addressfamily);\r
+ if ((err = sk_addr_error(addr)) != NULL) {\r
+ sk_addr_free(addr);\r
+ return err;\r
+ }\r
+\r
+ /*\r
+ * Open socket.\r
+ */\r
+ pr = snew(struct PFwdPrivate);\r
+ pr->buffer = NULL;\r
+ pr->fn = &fn_table;\r
+ pr->throttled = pr->throttle_override = 0;\r
+ pr->ready = 1;\r
+ pr->c = c;\r
+ pr->backhandle = NULL; /* we shouldn't need this */\r
+ pr->dynamic = 0;\r
+\r
+ pr->s = *s = new_connection(addr, dummy_realhost, port,\r
+ 0, 1, 0, 0, (Plug) pr, cfg);\r
+ if ((err = sk_socket_error(*s)) != NULL) {\r
+ sfree(pr);\r
+ return err;\r
+ }\r
+\r
+ sk_set_private_ptr(*s, pr);\r
+ return NULL;\r
+}\r
+\r
+/*\r
+ called when someone connects to the local port\r
+ */\r
+\r
+static int pfd_accepting(Plug p, OSSocket sock)\r
+{\r
+ static const struct plug_function_table fn_table = {\r
+ pfd_log,\r
+ pfd_closing,\r
+ pfd_receive,\r
+ pfd_sent,\r
+ NULL\r
+ };\r
+ struct PFwdPrivate *pr, *org;\r
+ Socket s;\r
+ const char *err;\r
+\r
+ org = (struct PFwdPrivate *)p;\r
+ pr = snew(struct PFwdPrivate);\r
+ pr->buffer = NULL;\r
+ pr->fn = &fn_table;\r
+\r
+ pr->c = NULL;\r
+ pr->backhandle = org->backhandle;\r
+\r
+ pr->s = s = sk_register(sock, (Plug) pr);\r
+ if ((err = sk_socket_error(s)) != NULL) {\r
+ sfree(pr);\r
+ return err != NULL;\r
+ }\r
+\r
+ sk_set_private_ptr(s, pr);\r
+\r
+ pr->throttled = pr->throttle_override = 0;\r
+ pr->ready = 0;\r
+\r
+ if (org->dynamic) {\r
+ pr->dynamic = 1;\r
+ pr->port = 0; /* "hostname" buffer is so far empty */\r
+ sk_set_frozen(s, 0); /* we want to receive SOCKS _now_! */\r
+ } else {\r
+ pr->dynamic = 0;\r
+ strcpy(pr->hostname, org->hostname);\r
+ pr->port = org->port; \r
+ pr->c = new_sock_channel(org->backhandle, s);\r
+\r
+ if (pr->c == NULL) {\r
+ sfree(pr);\r
+ return 1;\r
+ } else {\r
+ /* asks to forward to the specified host/port for this */\r
+ ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");\r
+ }\r
+ }\r
+\r
+ return 0;\r
+}\r
+\r
+\r
+/* Add a new forwarding from port -> desthost:destport\r
+ sets up a listener on the local machine on (srcaddr:)port\r
+ */\r
+const char *pfd_addforward(char *desthost, int destport, char *srcaddr,\r
+ int port, void *backhandle, const Config *cfg,\r
+ void **sockdata, int address_family)\r
+{\r
+ static const struct plug_function_table fn_table = {\r
+ pfd_log,\r
+ pfd_closing,\r
+ pfd_receive, /* should not happen... */\r
+ pfd_sent, /* also should not happen */\r
+ pfd_accepting\r
+ };\r
+\r
+ const char *err;\r
+ struct PFwdPrivate *pr;\r
+ Socket s;\r
+\r
+ /*\r
+ * Open socket.\r
+ */\r
+ pr = snew(struct PFwdPrivate);\r
+ pr->buffer = NULL;\r
+ pr->fn = &fn_table;\r
+ pr->c = NULL;\r
+ if (desthost) {\r
+ strcpy(pr->hostname, desthost);\r
+ pr->port = destport;\r
+ pr->dynamic = 0;\r
+ } else\r
+ pr->dynamic = 1;\r
+ pr->throttled = pr->throttle_override = 0;\r
+ pr->ready = 0;\r
+ pr->backhandle = backhandle;\r
+\r
+ pr->s = s = new_listener(srcaddr, port, (Plug) pr,\r
+ !cfg->lport_acceptall, cfg, address_family);\r
+ if ((err = sk_socket_error(s)) != NULL) {\r
+ sfree(pr);\r
+ return err;\r
+ }\r
+\r
+ sk_set_private_ptr(s, pr);\r
+\r
+ *sockdata = (void *)s;\r
+\r
+ return NULL;\r
+}\r
+\r
+void pfd_close(Socket s)\r
+{\r
+ struct PFwdPrivate *pr;\r
+\r
+ if (!s)\r
+ return;\r
+\r
+ pr = (struct PFwdPrivate *) sk_get_private_ptr(s);\r
+\r
+ sfree(pr->buffer);\r
+ sfree(pr);\r
+\r
+ sk_close(s);\r
+}\r
+\r
+/*\r
+ * Terminate a listener.\r
+ */\r
+void pfd_terminate(void *sv)\r
+{\r
+ pfd_close((Socket)sv);\r
+}\r
+\r
+void pfd_unthrottle(Socket s)\r
+{\r
+ struct PFwdPrivate *pr;\r
+ if (!s)\r
+ return;\r
+ pr = (struct PFwdPrivate *) sk_get_private_ptr(s);\r
+\r
+ pr->throttled = 0;\r
+ sk_set_frozen(s, pr->throttled || pr->throttle_override);\r
+}\r
+\r
+void pfd_override_throttle(Socket s, int enable)\r
+{\r
+ struct PFwdPrivate *pr;\r
+ if (!s)\r
+ return;\r
+ pr = (struct PFwdPrivate *) sk_get_private_ptr(s);\r
+\r
+ pr->throttle_override = enable;\r
+ sk_set_frozen(s, pr->throttled || pr->throttle_override);\r
+}\r
+\r
+/*\r
+ * Called to send data down the raw connection.\r
+ */\r
+int pfd_send(Socket s, char *data, int len)\r
+{\r
+ if (s == NULL)\r
+ return 0;\r
+ return sk_write(s, data, len);\r
+}\r
+\r
+\r
+void pfd_confirm(Socket s)\r
+{\r
+ struct PFwdPrivate *pr;\r
+\r
+ if (s == NULL)\r
+ return;\r
+\r
+ pr = (struct PFwdPrivate *) sk_get_private_ptr(s);\r
+ pr->ready = 1;\r
+ sk_set_frozen(s, 0);\r
+ sk_write(s, NULL, 0);\r
+ if (pr->buffer) {\r
+ sshfwd_write(pr->c, pr->buffer, pr->buflen);\r
+ sfree(pr->buffer);\r
+ pr->buffer = NULL;\r
+ }\r
+}\r
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