2 * Unix networking abstraction.
11 #include <sys/types.h>
12 #include <sys/socket.h>
13 #include <sys/ioctl.h>
14 #include <arpa/inet.h>
15 #include <netinet/in.h>
16 #include <netinet/tcp.h>
19 #define DEFINE_PLUG_METHOD_MACROS
24 #define ipv4_is_loopback(addr) (inet_netof(addr) == IN_LOOPBACKNET)
27 struct socket_function_table *fn;
28 /* the above variable absolutely *must* be the first in this structure */
36 int frozen; /* this causes readability notifications to be ignored */
37 int frozen_readable; /* this means we missed at least one readability
38 * notification while we were frozen */
39 int localhost_only; /* for listening sockets */
42 int oobpending; /* is there OOB data available to read? */
44 int pending_error; /* in case send() returns error */
49 * We used to typedef struct Socket_tag *Socket.
51 * Since we have made the networking abstraction slightly more
52 * abstract, Socket no longer means a tcp socket (it could mean
53 * an ssl socket). So now we must use Actual_Socket when we know
54 * we are talking about a tcp socket.
56 typedef struct Socket_tag *Actual_Socket;
61 * Which address family this address belongs to. AF_INET for
62 * IPv4; AF_INET6 for IPv6; AF_UNSPEC indicates that name
63 * resolution has not been done and a simple host name is held
64 * in this SockAddr structure.
67 unsigned long address; /* Address IPv4 style. */
69 struct addrinfo *ai; /* Address IPv6 style. */
71 char hostname[512]; /* Store an unresolved host name. */
74 static tree234 *sktree;
76 static int cmpfortree(void *av, void *bv)
78 Actual_Socket a = (Actual_Socket) av, b = (Actual_Socket) bv;
79 int as = a->s, bs = b->s;
87 static int cmpforsearch(void *av, void *bv)
89 Actual_Socket b = (Actual_Socket) bv;
90 int as = (int) av, bs = b->s;
100 sktree = newtree234(cmpfortree);
103 void sk_cleanup(void)
109 for (i = 0; (s = index234(sktree, i)) != NULL; i++) {
115 char *error_string(int error)
117 return strerror(error);
120 SockAddr sk_namelookup(char *host, char **canonicalname)
122 SockAddr ret = smalloc(sizeof(struct SockAddr_tag));
124 struct hostent *h = NULL;
127 /* Clear the structure and default to IPv4. */
128 memset(ret, 0, sizeof(struct SockAddr_tag));
129 ret->family = 0; /* We set this one when we have resolved the host. */
133 if ((a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
135 if (getaddrinfo(host, NULL, NULL, &ret->ai) == 0) {
136 ret->family = ret->ai->ai_family;
141 * Otherwise use the IPv4-only gethostbyname... (NOTE:
142 * we don't use gethostbyname as a fallback!)
144 if (ret->family == 0) {
145 /*debug(("Resolving \"%s\" with gethostbyname() (IPv4 only)...\n", host)); */
146 if ( (h = gethostbyname(host)) )
147 ret->family = AF_INET;
149 if (ret->family == 0) {
150 ret->error = (h_errno == HOST_NOT_FOUND ||
151 h_errno == NO_DATA ||
152 h_errno == NO_ADDRESS ? "Host does not exist" :
153 h_errno == TRY_AGAIN ?
154 "Temporary name service failure" :
155 "gethostbyname: unknown error");
161 /* If we got an address info use that... */
164 /* Are we in IPv4 fallback mode? */
165 /* We put the IPv4 address into the a variable so we can further-on use the IPv4 code... */
166 if (ret->family == AF_INET)
168 (char *) &((struct sockaddr_in *) ret->ai->
169 ai_addr)->sin_addr, sizeof(a));
171 /* Now let's find that canonicalname... */
172 if (getnameinfo((struct sockaddr *) ret->ai->ai_addr,
174 AF_INET ? sizeof(struct sockaddr_in) :
175 sizeof(struct sockaddr_in6), realhost,
176 sizeof(realhost), NULL, 0, 0) != 0) {
177 strncpy(realhost, host, sizeof(realhost));
180 /* We used the IPv4-only gethostbyname()... */
184 memcpy(&a, h->h_addr, sizeof(a));
185 /* This way we are always sure the h->h_name is valid :) */
186 strncpy(realhost, h->h_name, sizeof(realhost));
190 * This must be a numeric IPv4 address because it caused a
191 * success return from inet_addr.
193 ret->family = AF_INET;
194 strncpy(realhost, host, sizeof(realhost));
196 ret->address = ntohl(a);
197 realhost[lenof(realhost)-1] = '\0';
198 *canonicalname = smalloc(1+strlen(realhost));
199 strcpy(*canonicalname, realhost);
203 SockAddr sk_nonamelookup(char *host)
205 SockAddr ret = smalloc(sizeof(struct SockAddr_tag));
206 ret->family = AF_UNSPEC;
207 strncpy(ret->hostname, host, lenof(ret->hostname));
208 ret->hostname[lenof(ret->hostname)-1] = '\0';
212 void sk_getaddr(SockAddr addr, char *buf, int buflen)
215 if (addr->family == AF_INET6) {
216 FIXME; /* I don't know how to get a text form of an IPv6 address. */
219 if (addr->family == AF_INET) {
221 a.s_addr = htonl(addr->address);
222 strncpy(buf, inet_ntoa(a), buflen);
223 buf[buflen-1] = '\0';
225 assert(addr->family == AF_UNSPEC);
226 strncpy(buf, addr->hostname, buflen);
227 buf[buflen-1] = '\0';
231 int sk_hostname_is_local(char *name)
233 return !strcmp(name, "localhost");
236 int sk_address_is_local(SockAddr addr)
239 if (addr->family == AF_INET6) {
240 FIXME; /* someone who can compile for IPV6 had better do this bit */
243 if (addr->family == AF_INET) {
245 a.s_addr = htonl(addr->address);
246 return ipv4_is_loopback(a);
248 assert(addr->family == AF_UNSPEC);
249 return 0; /* we don't know; assume not */
253 int sk_addrtype(SockAddr addr)
255 return (addr->family == AF_INET ? ADDRTYPE_IPV4 :
257 addr->family == AF_INET6 ? ADDRTYPE_IPV6 :
262 void sk_addrcopy(SockAddr addr, char *buf)
264 assert(addr->family != AF_UNSPEC);
266 if (addr->family == AF_INET6) {
267 memcpy(buf, (char*) addr->ai, 16);
270 if (addr->family == AF_INET) {
272 a.s_addr = htonl(addr->address);
273 memcpy(buf, (char*) &a.s_addr, 4);
277 void sk_addr_free(SockAddr addr)
282 static Plug sk_tcp_plug(Socket sock, Plug p)
284 Actual_Socket s = (Actual_Socket) sock;
291 static void sk_tcp_flush(Socket s)
294 * We send data to the socket as soon as we can anyway,
295 * so we don't need to do anything here. :-)
299 static void sk_tcp_close(Socket s);
300 static int sk_tcp_write(Socket s, char *data, int len);
301 static int sk_tcp_write_oob(Socket s, char *data, int len);
302 static void sk_tcp_set_private_ptr(Socket s, void *ptr);
303 static void *sk_tcp_get_private_ptr(Socket s);
304 static void sk_tcp_set_frozen(Socket s, int is_frozen);
305 static char *sk_tcp_socket_error(Socket s);
307 Socket sk_register(void *sock, Plug plug)
309 static struct socket_function_table fn_table = {
315 sk_tcp_set_private_ptr,
316 sk_tcp_get_private_ptr,
324 * Create Socket structure.
326 ret = smalloc(sizeof(struct Socket_tag));
330 bufchain_init(&ret->output_data);
331 ret->writable = 1; /* to start with */
332 ret->sending_oob = 0;
334 ret->frozen_readable = 0;
335 ret->localhost_only = 0; /* unused, but best init anyway */
336 ret->pending_error = 0;
337 ret->oobpending = FALSE;
343 ret->error = error_string(errno);
354 Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
355 int nodelay, Plug plug)
357 static struct socket_function_table fn_table = {
363 sk_tcp_set_private_ptr,
364 sk_tcp_get_private_ptr,
371 struct sockaddr_in6 a6;
373 struct sockaddr_in a;
379 * Create Socket structure.
381 ret = smalloc(sizeof(struct Socket_tag));
385 bufchain_init(&ret->output_data);
386 ret->connected = 0; /* to start with */
387 ret->writable = 0; /* to start with */
388 ret->sending_oob = 0;
390 ret->frozen_readable = 0;
391 ret->localhost_only = 0; /* unused, but best init anyway */
392 ret->pending_error = 0;
393 ret->oobpending = FALSE;
399 assert(addr->family != AF_UNSPEC);
400 s = socket(addr->family, SOCK_STREAM, 0);
404 ret->error = error_string(errno);
408 ret->oobinline = oobinline;
411 setsockopt(s, SOL_SOCKET, SO_OOBINLINE, (void *) &b, sizeof(b));
416 setsockopt(s, IPPROTO_TCP, TCP_NODELAY, (void *) &b, sizeof(b));
420 * Bind to local address.
423 localport = 1023; /* count from 1023 downwards */
425 localport = 0; /* just use port 0 (ie kernel picks) */
427 /* Loop round trying to bind */
432 if (addr->family == AF_INET6) {
433 memset(&a6, 0, sizeof(a6));
434 a6.sin6_family = AF_INET6;
435 /*a6.sin6_addr = in6addr_any; *//* == 0 */
436 a6.sin6_port = htons(localport);
440 a.sin_family = AF_INET;
441 a.sin_addr.s_addr = htonl(INADDR_ANY);
442 a.sin_port = htons(localport);
445 retcode = bind(s, (addr->family == AF_INET6 ?
446 (struct sockaddr *) &a6 :
447 (struct sockaddr *) &a),
449 AF_INET6 ? sizeof(a6) : sizeof(a)));
451 retcode = bind(s, (struct sockaddr *) &a, sizeof(a));
458 if (err != EADDRINUSE) /* failed, for a bad reason */
463 break; /* we're only looping once */
466 break; /* we might have got to the end */
470 ret->error = error_string(err);
475 * Connect to remote address.
478 if (addr->family == AF_INET6) {
479 memset(&a, 0, sizeof(a));
480 a6.sin6_family = AF_INET6;
481 a6.sin6_port = htons((short) port);
483 ((struct sockaddr_in6 *) addr->ai->ai_addr)->sin6_addr;
487 a.sin_family = AF_INET;
488 a.sin_addr.s_addr = htonl(addr->address);
489 a.sin_port = htons((short) port);
494 connect(s, ((addr->family == AF_INET6) ?
495 (struct sockaddr *) &a6 : (struct sockaddr *) &a),
496 (addr->family == AF_INET6) ? sizeof(a6) : sizeof(a))
498 connect(s, (struct sockaddr *) &a, sizeof(a))
502 * FIXME: We are prepared to receive EWOULDBLOCK here,
503 * because we might want the connection to be made
504 * asynchronously; but how do we actually arrange this in
507 if ( errno != EWOULDBLOCK ) {
508 ret->error = error_string(errno);
513 * If we _don't_ get EWOULDBLOCK, the connect has completed
514 * and we should set the socket as connected and writable.
525 Socket sk_newlistener(char *srcaddr, int port, Plug plug, int local_host_only)
527 static struct socket_function_table fn_table = {
533 sk_tcp_set_private_ptr,
534 sk_tcp_get_private_ptr,
541 struct sockaddr_in6 a6;
543 struct sockaddr_in a;
550 * Create Socket structure.
552 ret = smalloc(sizeof(struct Socket_tag));
556 bufchain_init(&ret->output_data);
557 ret->writable = 0; /* to start with */
558 ret->sending_oob = 0;
560 ret->frozen_readable = 0;
561 ret->localhost_only = local_host_only;
562 ret->pending_error = 0;
563 ret->oobpending = FALSE;
569 s = socket(AF_INET, SOCK_STREAM, 0);
573 ret->error = error_string(errno);
579 setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&on, sizeof(on));
582 if (addr->family == AF_INET6) {
583 memset(&a6, 0, sizeof(a6));
584 a6.sin6_family = AF_INET6;
585 /* FIXME: srcaddr is ignored for IPv6, because I (SGT) don't
586 * know how to do it. :-) */
588 a6.sin6_addr = in6addr_loopback;
590 a6.sin6_addr = in6addr_any;
591 a6.sin6_port = htons(port);
596 a.sin_family = AF_INET;
599 * Bind to source address. First try an explicitly
603 a.sin_addr.s_addr = inet_addr(srcaddr);
604 if (a.sin_addr.s_addr != INADDR_NONE) {
605 /* Override localhost_only with specified listen addr. */
606 ret->localhost_only = ipv4_is_loopback(a.sin_addr);
612 * ... and failing that, go with one of the standard ones.
616 a.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
618 a.sin_addr.s_addr = htonl(INADDR_ANY);
621 a.sin_port = htons((short)port);
624 retcode = bind(s, (addr->family == AF_INET6 ?
625 (struct sockaddr *) &a6 :
626 (struct sockaddr *) &a),
628 AF_INET6 ? sizeof(a6) : sizeof(a)));
630 retcode = bind(s, (struct sockaddr *) &a, sizeof(a));
639 ret->error = error_string(err);
644 if (listen(s, SOMAXCONN) < 0) {
646 ret->error = error_string(errno);
655 static void sk_tcp_close(Socket sock)
657 Actual_Socket s = (Actual_Socket) sock;
665 * The function which tries to send on a socket once it's deemed
668 void try_send(Actual_Socket s)
670 while (s->sending_oob || bufchain_size(&s->output_data) > 0) {
676 if (s->sending_oob) {
677 urgentflag = MSG_OOB;
678 len = s->sending_oob;
682 bufchain_prefix(&s->output_data, &data, &len);
684 nsent = send(s->s, data, len, urgentflag);
685 noise_ultralight(nsent);
687 err = (nsent < 0 ? errno : 0);
688 if (err == EWOULDBLOCK) {
690 * Perfectly normal: we've sent all we can for the moment.
694 } else if (nsent == 0 ||
695 err == ECONNABORTED || err == ECONNRESET) {
697 * If send() returns CONNABORTED or CONNRESET, we
698 * unfortunately can't just call plug_closing(),
699 * because it's quite likely that we're currently
700 * _in_ a call from the code we'd be calling back
701 * to, so we'd have to make half the SSH code
702 * reentrant. Instead we flag a pending error on
703 * the socket, to be dealt with (by calling
704 * plug_closing()) at some suitable future moment.
706 s->pending_error = err;
709 /* We're inside the Unix frontend here, so we know
710 * that the frontend handle is unnecessary. */
711 logevent(NULL, error_string(err));
712 fatalbox("%s", error_string(err));
715 if (s->sending_oob) {
717 memmove(s->oobdata, s->oobdata+nsent, len-nsent);
718 s->sending_oob = len - nsent;
723 bufchain_consume(&s->output_data, nsent);
729 static int sk_tcp_write(Socket sock, char *buf, int len)
731 Actual_Socket s = (Actual_Socket) sock;
734 * Add the data to the buffer list on the socket.
736 bufchain_add(&s->output_data, buf, len);
739 * Now try sending from the start of the buffer list.
744 return bufchain_size(&s->output_data);
747 static int sk_tcp_write_oob(Socket sock, char *buf, int len)
749 Actual_Socket s = (Actual_Socket) sock;
752 * Replace the buffer list on the socket with the data.
754 bufchain_clear(&s->output_data);
755 assert(len <= sizeof(s->oobdata));
756 memcpy(s->oobdata, buf, len);
757 s->sending_oob = len;
760 * Now try sending from the start of the buffer list.
765 return s->sending_oob;
768 int select_result(int fd, int event)
772 char buf[20480]; /* nice big buffer for plenty of speed */
776 /* Find the Socket structure */
777 s = find234(sktree, (void *) fd, cmpforsearch);
779 return 1; /* boggle */
781 noise_ultralight(event);
784 #ifdef FIXME_NONBLOCKING_CONNECTIONS
785 case FIXME: /* connected */
786 s->connected = s->writable = 1;
789 case 4: /* exceptional */
792 * On a non-oobinline socket, this indicates that we
793 * can immediately perform an OOB read and get back OOB
794 * data, which we will send to the back end with
795 * type==2 (urgent data).
797 ret = recv(s->s, buf, sizeof(buf), MSG_OOB);
798 noise_ultralight(ret);
800 char *str = (ret == 0 ? "Internal networking trouble" :
801 error_string(errno));
802 /* We're inside the Unix frontend here, so we know
803 * that the frontend handle is unnecessary. */
807 return plug_receive(s->plug, 2, buf, ret);
813 * If we reach here, this is an oobinline socket, which
814 * means we should set s->oobpending and then deal with it
815 * when we get called for the readability event (which
816 * should also occur).
818 s->oobpending = TRUE;
820 case 1: /* readable; also acceptance */
823 * On a listening socket, the readability event means a
824 * connection is ready to be accepted.
826 struct sockaddr_in isa;
827 int addrlen = sizeof(struct sockaddr_in);
828 int t; /* socket of connection */
830 memset(&isa, 0, sizeof(struct sockaddr_in));
832 t = accept(s->s,(struct sockaddr *)&isa,&addrlen);
837 if (s->localhost_only && !ipv4_is_loopback(isa.sin_addr)) {
838 close(t); /* someone let nonlocal through?! */
839 } else if (plug_accepting(s->plug, (void*)t)) {
840 close(t); /* denied or error */
846 * If we reach here, this is not a listening socket, so
847 * readability really means readability.
850 /* In the case the socket is still frozen, we don't even bother */
852 s->frozen_readable = 1;
857 * We have received data on the socket. For an oobinline
858 * socket, this might be data _before_ an urgent pointer,
859 * in which case we send it to the back end with type==1
860 * (data prior to urgent).
862 if (s->oobinline && s->oobpending) {
864 if (ioctl(s->s, SIOCATMARK, &atmark) == 0 && atmark)
865 s->oobpending = FALSE; /* clear this indicator */
869 ret = recv(s->s, buf, s->oobpending ? 1 : sizeof(buf), 0);
870 noise_ultralight(ret);
872 if (errno == EWOULDBLOCK) {
877 return plug_closing(s->plug, error_string(errno), errno, 0);
878 } else if (0 == ret) {
879 return plug_closing(s->plug, NULL, 0, 0);
881 return plug_receive(s->plug, atmark ? 0 : 1, buf, ret);
884 case 2: /* writable */
886 int bufsize_before, bufsize_after;
888 bufsize_before = s->sending_oob + bufchain_size(&s->output_data);
890 bufsize_after = s->sending_oob + bufchain_size(&s->output_data);
891 if (bufsize_after < bufsize_before)
892 plug_sent(s->plug, bufsize_after);
901 * Deal with socket errors detected in try_send().
903 void net_pending_errors(void)
909 * This might be a fiddly business, because it's just possible
910 * that handling a pending error on one socket might cause
911 * others to be closed. (I can't think of any reason this might
912 * happen in current SSH implementation, but to maintain
913 * generality of this network layer I'll assume the worst.)
915 * So what we'll do is search the socket list for _one_ socket
916 * with a pending error, and then handle it, and then search
917 * the list again _from the beginning_. Repeat until we make a
918 * pass with no socket errors present. That way we are
919 * protected against the socket list changing under our feet.
923 for (i = 0; (s = index234(sktree, i)) != NULL; i++) {
924 if (s->pending_error) {
926 * An error has occurred on this socket. Pass it to the
929 plug_closing(s->plug, error_string(s->pending_error),
930 s->pending_error, 0);
938 * Each socket abstraction contains a `void *' private field in
939 * which the client can keep state.
941 static void sk_tcp_set_private_ptr(Socket sock, void *ptr)
943 Actual_Socket s = (Actual_Socket) sock;
944 s->private_ptr = ptr;
947 static void *sk_tcp_get_private_ptr(Socket sock)
949 Actual_Socket s = (Actual_Socket) sock;
950 return s->private_ptr;
954 * Special error values are returned from sk_namelookup and sk_new
955 * if there's a problem. These functions extract an error message,
956 * or return NULL if there's no problem.
958 char *sk_addr_error(SockAddr addr)
962 static char *sk_tcp_socket_error(Socket sock)
964 Actual_Socket s = (Actual_Socket) sock;
968 static void sk_tcp_set_frozen(Socket sock, int is_frozen)
970 Actual_Socket s = (Actual_Socket) sock;
971 if (s->frozen == is_frozen)
973 s->frozen = is_frozen;
974 if (!is_frozen && s->frozen_readable) {
976 recv(s->s, &c, 1, MSG_PEEK);
978 s->frozen_readable = 0;
982 * For Unix select()-based frontends: enumerate all sockets
983 * currently active, and state whether we currently wish to receive
984 * select events on them for reading, writing and exceptional
987 static void set_rwx(Actual_Socket s, int *rwx)
990 if (s->connected && !s->frozen)
991 val |= 1 | 4; /* read, except */
992 if (bufchain_size(&s->output_data))
993 val |= 2; /* write */
995 val |= 1; /* read == accept */
999 int first_socket(int *state, int *rwx)
1003 s = index234(sktree, (*state)++);
1006 return s ? s->s : -1;
1009 int next_socket(int *state, int *rwx)
1011 Actual_Socket s = index234(sktree, (*state)++);
1014 return s ? s->s : -1;
1017 int net_service_lookup(char *service)
1020 se = getservbyname(service, NULL);
1022 return ntohs(se->s_port);