/* * Unix networking abstraction. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #define DEFINE_PLUG_METHOD_MACROS #include "putty.h" #include "network.h" #include "tree234.h" #define ipv4_is_loopback(addr) (inet_netof(addr) == IN_LOOPBACKNET) struct Socket_tag { struct socket_function_table *fn; /* the above variable absolutely *must* be the first in this structure */ char *error; int s; Plug plug; void *private_ptr; bufchain output_data; int connected; int writable; int frozen; /* this causes readability notifications to be ignored */ int frozen_readable; /* this means we missed at least one readability * notification while we were frozen */ int localhost_only; /* for listening sockets */ char oobdata[1]; int sending_oob; int oobpending; /* is there OOB data available to read? */ int oobinline; int pending_error; /* in case send() returns error */ int listener; }; /* * We used to typedef struct Socket_tag *Socket. * * Since we have made the networking abstraction slightly more * abstract, Socket no longer means a tcp socket (it could mean * an ssl socket). So now we must use Actual_Socket when we know * we are talking about a tcp socket. */ typedef struct Socket_tag *Actual_Socket; struct SockAddr_tag { char *error; /* * Which address family this address belongs to. AF_INET for * IPv4; AF_INET6 for IPv6; AF_UNSPEC indicates that name * resolution has not been done and a simple host name is held * in this SockAddr structure. */ int family; unsigned long address; /* Address IPv4 style. */ #ifdef IPV6 struct addrinfo *ai; /* Address IPv6 style. */ #endif char hostname[512]; /* Store an unresolved host name. */ }; static tree234 *sktree; static void uxsel_tell(Actual_Socket s); static int cmpfortree(void *av, void *bv) { Actual_Socket a = (Actual_Socket) av, b = (Actual_Socket) bv; int as = a->s, bs = b->s; if (as < bs) return -1; if (as > bs) return +1; return 0; } static int cmpforsearch(void *av, void *bv) { Actual_Socket b = (Actual_Socket) bv; int as = (int) av, bs = b->s; if (as < bs) return -1; if (as > bs) return +1; return 0; } void sk_init(void) { sktree = newtree234(cmpfortree); } void sk_cleanup(void) { Actual_Socket s; int i; if (sktree) { for (i = 0; (s = index234(sktree, i)) != NULL; i++) { close(s->s); } } } char *error_string(int error) { return strerror(error); } SockAddr sk_namelookup(const char *host, char **canonicalname) { SockAddr ret = snew(struct SockAddr_tag); unsigned long a; struct hostent *h = NULL; char realhost[8192]; /* Clear the structure and default to IPv4. */ memset(ret, 0, sizeof(struct SockAddr_tag)); ret->family = 0; /* We set this one when we have resolved the host. */ *realhost = '\0'; ret->error = NULL; if ((a = inet_addr(host)) == (unsigned long) INADDR_NONE) { #ifdef IPV6 if (getaddrinfo(host, NULL, NULL, &ret->ai) == 0) { ret->family = ret->ai->ai_family; } else #endif { /* * Otherwise use the IPv4-only gethostbyname... (NOTE: * we don't use gethostbyname as a fallback!) */ if (ret->family == 0) { /*debug(("Resolving \"%s\" with gethostbyname() (IPv4 only)...\n", host)); */ if ( (h = gethostbyname(host)) ) ret->family = AF_INET; } if (ret->family == 0) { ret->error = (h_errno == HOST_NOT_FOUND || h_errno == NO_DATA || h_errno == NO_ADDRESS ? "Host does not exist" : h_errno == TRY_AGAIN ? "Temporary name service failure" : "gethostbyname: unknown error"); return ret; } } #ifdef IPV6 /* If we got an address info use that... */ if (ret->ai) { /* Are we in IPv4 fallback mode? */ /* We put the IPv4 address into the a variable so we can further-on use the IPv4 code... */ if (ret->family == AF_INET) memcpy(&a, (char *) &((struct sockaddr_in *) ret->ai-> ai_addr)->sin_addr, sizeof(a)); /* Now let's find that canonicalname... */ if (getnameinfo((struct sockaddr *) ret->ai->ai_addr, ret->family == AF_INET ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6), realhost, sizeof(realhost), NULL, 0, 0) != 0) { strncpy(realhost, host, sizeof(realhost)); } } /* We used the IPv4-only gethostbyname()... */ else #endif { memcpy(&a, h->h_addr, sizeof(a)); /* This way we are always sure the h->h_name is valid :) */ strncpy(realhost, h->h_name, sizeof(realhost)); } } else { /* * This must be a numeric IPv4 address because it caused a * success return from inet_addr. */ ret->family = AF_INET; strncpy(realhost, host, sizeof(realhost)); } ret->address = ntohl(a); realhost[lenof(realhost)-1] = '\0'; *canonicalname = snewn(1+strlen(realhost), char); strcpy(*canonicalname, realhost); return ret; } SockAddr sk_nonamelookup(const char *host) { SockAddr ret = snew(struct SockAddr_tag); ret->error = NULL; ret->family = AF_UNSPEC; strncpy(ret->hostname, host, lenof(ret->hostname)); ret->hostname[lenof(ret->hostname)-1] = '\0'; return ret; } void sk_getaddr(SockAddr addr, char *buf, int buflen) { #ifdef IPV6 if (addr->family == AF_INET6) { FIXME; /* I don't know how to get a text form of an IPv6 address. */ } else #endif if (addr->family == AF_INET) { struct in_addr a; a.s_addr = htonl(addr->address); strncpy(buf, inet_ntoa(a), buflen); buf[buflen-1] = '\0'; } else { assert(addr->family == AF_UNSPEC); strncpy(buf, addr->hostname, buflen); buf[buflen-1] = '\0'; } } int sk_hostname_is_local(char *name) { return !strcmp(name, "localhost"); } int sk_address_is_local(SockAddr addr) { #ifdef IPV6 if (addr->family == AF_INET6) { FIXME; /* someone who can compile for IPV6 had better do this bit */ } else #endif if (addr->family == AF_INET) { struct in_addr a; a.s_addr = htonl(addr->address); return ipv4_is_loopback(a); } else { assert(addr->family == AF_UNSPEC); return 0; /* we don't know; assume not */ } } int sk_addrtype(SockAddr addr) { return (addr->family == AF_INET ? ADDRTYPE_IPV4 : #ifdef IPV6 addr->family == AF_INET6 ? ADDRTYPE_IPV6 : #endif ADDRTYPE_NAME); } void sk_addrcopy(SockAddr addr, char *buf) { assert(addr->family != AF_UNSPEC); #ifdef IPV6 if (addr->family == AF_INET6) { memcpy(buf, (char*) addr->ai, 16); } else #endif if (addr->family == AF_INET) { struct in_addr a; a.s_addr = htonl(addr->address); memcpy(buf, (char*) &a.s_addr, 4); } } void sk_addr_free(SockAddr addr) { sfree(addr); } static Plug sk_tcp_plug(Socket sock, Plug p) { Actual_Socket s = (Actual_Socket) sock; Plug ret = s->plug; if (p) s->plug = p; return ret; } static void sk_tcp_flush(Socket s) { /* * We send data to the socket as soon as we can anyway, * so we don't need to do anything here. :-) */ } static void sk_tcp_close(Socket s); static int sk_tcp_write(Socket s, const char *data, int len); static int sk_tcp_write_oob(Socket s, const char *data, int len); static void sk_tcp_set_private_ptr(Socket s, void *ptr); static void *sk_tcp_get_private_ptr(Socket s); static void sk_tcp_set_frozen(Socket s, int is_frozen); static char *sk_tcp_socket_error(Socket s); static struct socket_function_table tcp_fn_table = { sk_tcp_plug, sk_tcp_close, sk_tcp_write, sk_tcp_write_oob, sk_tcp_flush, sk_tcp_set_private_ptr, sk_tcp_get_private_ptr, sk_tcp_set_frozen, sk_tcp_socket_error }; Socket sk_register(void *sock, Plug plug) { Actual_Socket ret; /* * Create Socket structure. */ ret = snew(struct Socket_tag); ret->fn = &tcp_fn_table; ret->error = NULL; ret->plug = plug; bufchain_init(&ret->output_data); ret->writable = 1; /* to start with */ ret->sending_oob = 0; ret->frozen = 1; ret->frozen_readable = 0; ret->localhost_only = 0; /* unused, but best init anyway */ ret->pending_error = 0; ret->oobpending = FALSE; ret->listener = 0; ret->s = (int)sock; if (ret->s < 0) { ret->error = error_string(errno); return (Socket) ret; } ret->oobinline = 0; uxsel_tell(ret); add234(sktree, ret); return (Socket) ret; } Socket sk_new(SockAddr addr, int port, int privport, int oobinline, int nodelay, Plug plug) { int s; #ifdef IPV6 struct sockaddr_in6 a6; #endif struct sockaddr_in a; int err; Actual_Socket ret; short localport; /* * Create Socket structure. */ ret = snew(struct Socket_tag); ret->fn = &tcp_fn_table; ret->error = NULL; ret->plug = plug; bufchain_init(&ret->output_data); ret->connected = 0; /* to start with */ ret->writable = 0; /* to start with */ ret->sending_oob = 0; ret->frozen = 0; ret->frozen_readable = 0; ret->localhost_only = 0; /* unused, but best init anyway */ ret->pending_error = 0; ret->oobpending = FALSE; ret->listener = 0; /* * Open socket. */ assert(addr->family != AF_UNSPEC); s = socket(addr->family, SOCK_STREAM, 0); ret->s = s; if (s < 0) { ret->error = error_string(errno); return (Socket) ret; } ret->oobinline = oobinline; if (oobinline) { int b = TRUE; setsockopt(s, SOL_SOCKET, SO_OOBINLINE, (void *) &b, sizeof(b)); } if (nodelay) { int b = TRUE; setsockopt(s, IPPROTO_TCP, TCP_NODELAY, (void *) &b, sizeof(b)); } /* * Bind to local address. */ if (privport) localport = 1023; /* count from 1023 downwards */ else localport = 0; /* just use port 0 (ie kernel picks) */ /* Loop round trying to bind */ while (1) { int retcode; #ifdef IPV6 if (addr->family == AF_INET6) { memset(&a6, 0, sizeof(a6)); a6.sin6_family = AF_INET6; /*a6.sin6_addr = in6addr_any; *//* == 0 */ a6.sin6_port = htons(localport); } else #endif { a.sin_family = AF_INET; a.sin_addr.s_addr = htonl(INADDR_ANY); a.sin_port = htons(localport); } #ifdef IPV6 retcode = bind(s, (addr->family == AF_INET6 ? (struct sockaddr *) &a6 : (struct sockaddr *) &a), (addr->family == AF_INET6 ? sizeof(a6) : sizeof(a))); #else retcode = bind(s, (struct sockaddr *) &a, sizeof(a)); #endif if (retcode >= 0) { err = 0; break; /* done */ } else { err = errno; if (err != EADDRINUSE) /* failed, for a bad reason */ break; } if (localport == 0) break; /* we're only looping once */ localport--; if (localport == 0) break; /* we might have got to the end */ } if (err) { ret->error = error_string(err); return (Socket) ret; } /* * Connect to remote address. */ #ifdef IPV6 if (addr->family == AF_INET6) { memset(&a, 0, sizeof(a)); a6.sin6_family = AF_INET6; a6.sin6_port = htons((short) port); a6.sin6_addr = ((struct sockaddr_in6 *) addr->ai->ai_addr)->sin6_addr; } else #endif { a.sin_family = AF_INET; a.sin_addr.s_addr = htonl(addr->address); a.sin_port = htons((short) port); } { int i = 1; ioctl(s, FIONBIO, &i); } if (( #ifdef IPV6 connect(s, ((addr->family == AF_INET6) ? (struct sockaddr *) &a6 : (struct sockaddr *) &a), (addr->family == AF_INET6) ? sizeof(a6) : sizeof(a)) #else connect(s, (struct sockaddr *) &a, sizeof(a)) #endif ) < 0) { if ( errno != EINPROGRESS ) { ret->error = error_string(errno); return (Socket) ret; } } else { /* * If we _don't_ get EWOULDBLOCK, the connect has completed * and we should set the socket as connected and writable. */ ret->connected = 1; ret->writable = 1; } uxsel_tell(ret); add234(sktree, ret); return (Socket) ret; } Socket sk_newlistener(char *srcaddr, int port, Plug plug, int local_host_only) { int s; #ifdef IPV6 struct sockaddr_in6 a6; #endif struct sockaddr_in a; int err; Actual_Socket ret; int retcode; int on = 1; /* * Create Socket structure. */ ret = snew(struct Socket_tag); ret->fn = &tcp_fn_table; ret->error = NULL; ret->plug = plug; bufchain_init(&ret->output_data); ret->writable = 0; /* to start with */ ret->sending_oob = 0; ret->frozen = 0; ret->frozen_readable = 0; ret->localhost_only = local_host_only; ret->pending_error = 0; ret->oobpending = FALSE; ret->listener = 1; /* * Open socket. */ s = socket(AF_INET, SOCK_STREAM, 0); ret->s = s; if (s < 0) { ret->error = error_string(errno); return (Socket) ret; } ret->oobinline = 0; setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&on, sizeof(on)); #ifdef IPV6 if (addr->family == AF_INET6) { memset(&a6, 0, sizeof(a6)); a6.sin6_family = AF_INET6; /* FIXME: srcaddr is ignored for IPv6, because I (SGT) don't * know how to do it. :-) */ if (local_host_only) a6.sin6_addr = in6addr_loopback; else a6.sin6_addr = in6addr_any; a6.sin6_port = htons(port); } else #endif { int got_addr = 0; a.sin_family = AF_INET; /* * Bind to source address. First try an explicitly * specified one... */ if (srcaddr) { a.sin_addr.s_addr = inet_addr(srcaddr); if (a.sin_addr.s_addr != INADDR_NONE) { /* Override localhost_only with specified listen addr. */ ret->localhost_only = ipv4_is_loopback(a.sin_addr); got_addr = 1; } } /* * ... and failing that, go with one of the standard ones. */ if (!got_addr) { if (local_host_only) a.sin_addr.s_addr = htonl(INADDR_LOOPBACK); else a.sin_addr.s_addr = htonl(INADDR_ANY); } a.sin_port = htons((short)port); } #ifdef IPV6 retcode = bind(s, (addr->family == AF_INET6 ? (struct sockaddr *) &a6 : (struct sockaddr *) &a), (addr->family == AF_INET6 ? sizeof(a6) : sizeof(a))); #else retcode = bind(s, (struct sockaddr *) &a, sizeof(a)); #endif if (retcode >= 0) { err = 0; } else { err = errno; } if (err) { ret->error = error_string(err); return (Socket) ret; } if (listen(s, SOMAXCONN) < 0) { close(s); ret->error = error_string(errno); return (Socket) ret; } uxsel_tell(ret); add234(sktree, ret); return (Socket) ret; } static void sk_tcp_close(Socket sock) { Actual_Socket s = (Actual_Socket) sock; uxsel_del(s->s); del234(sktree, s); close(s->s); sfree(s); } int sk_getxdmdata(void *sock, unsigned long *ip, int *port) { Actual_Socket s = (Actual_Socket) sock; struct sockaddr_in addr; socklen_t addrlen; /* * We must check that this socket really _is_ an Actual_Socket. */ if (s->fn != &tcp_fn_table) return 0; /* failure */ /* * If we ever implement connecting to a local X server through * a Unix socket, we return 0xFFFFFFFF for the IP address and * our current pid for the port. Bizarre, but such is life. */ addrlen = sizeof(addr); if (getsockname(s->s, (struct sockaddr *)&addr, &addrlen) < 0 || addr.sin_family != AF_INET) return 0; *ip = ntohl(addr.sin_addr.s_addr); *port = ntohs(addr.sin_port); return 1; } /* * The function which tries to send on a socket once it's deemed * writable. */ void try_send(Actual_Socket s) { while (s->sending_oob || bufchain_size(&s->output_data) > 0) { int nsent; int err; void *data; int len, urgentflag; if (s->sending_oob) { urgentflag = MSG_OOB; len = s->sending_oob; data = &s->oobdata; } else { urgentflag = 0; bufchain_prefix(&s->output_data, &data, &len); } nsent = send(s->s, data, len, urgentflag); noise_ultralight(nsent); if (nsent <= 0) { err = (nsent < 0 ? errno : 0); if (err == EWOULDBLOCK) { /* * Perfectly normal: we've sent all we can for the moment. */ s->writable = FALSE; return; } else if (nsent == 0 || err == ECONNABORTED || err == ECONNRESET) { /* * If send() returns CONNABORTED or CONNRESET, we * unfortunately can't just call plug_closing(), * because it's quite likely that we're currently * _in_ a call from the code we'd be calling back * to, so we'd have to make half the SSH code * reentrant. Instead we flag a pending error on * the socket, to be dealt with (by calling * plug_closing()) at some suitable future moment. */ s->pending_error = err; return; } else { /* We're inside the Unix frontend here, so we know * that the frontend handle is unnecessary. */ logevent(NULL, error_string(err)); fatalbox("%s", error_string(err)); } } else { if (s->sending_oob) { if (nsent < len) { memmove(s->oobdata, s->oobdata+nsent, len-nsent); s->sending_oob = len - nsent; } else { s->sending_oob = 0; } } else { bufchain_consume(&s->output_data, nsent); } } } uxsel_tell(s); } static int sk_tcp_write(Socket sock, const char *buf, int len) { Actual_Socket s = (Actual_Socket) sock; /* * Add the data to the buffer list on the socket. */ bufchain_add(&s->output_data, buf, len); /* * Now try sending from the start of the buffer list. */ if (s->writable) try_send(s); return bufchain_size(&s->output_data); } static int sk_tcp_write_oob(Socket sock, const char *buf, int len) { Actual_Socket s = (Actual_Socket) sock; /* * Replace the buffer list on the socket with the data. */ bufchain_clear(&s->output_data); assert(len <= sizeof(s->oobdata)); memcpy(s->oobdata, buf, len); s->sending_oob = len; /* * Now try sending from the start of the buffer list. */ if (s->writable) try_send(s); return s->sending_oob; } static int net_select_result(int fd, int event) { int ret; int err; char buf[20480]; /* nice big buffer for plenty of speed */ Actual_Socket s; u_long atmark; /* Find the Socket structure */ s = find234(sktree, (void *) fd, cmpforsearch); if (!s) return 1; /* boggle */ noise_ultralight(event); switch (event) { case 4: /* exceptional */ if (!s->oobinline) { /* * On a non-oobinline socket, this indicates that we * can immediately perform an OOB read and get back OOB * data, which we will send to the back end with * type==2 (urgent data). */ ret = recv(s->s, buf, sizeof(buf), MSG_OOB); noise_ultralight(ret); if (ret <= 0) { char *str = (ret == 0 ? "Internal networking trouble" : error_string(errno)); /* We're inside the Unix frontend here, so we know * that the frontend handle is unnecessary. */ logevent(NULL, str); fatalbox("%s", str); } else { return plug_receive(s->plug, 2, buf, ret); } break; } /* * If we reach here, this is an oobinline socket, which * means we should set s->oobpending and then deal with it * when we get called for the readability event (which * should also occur). */ s->oobpending = TRUE; break; case 1: /* readable; also acceptance */ if (s->listener) { /* * On a listening socket, the readability event means a * connection is ready to be accepted. */ struct sockaddr_in isa; int addrlen = sizeof(struct sockaddr_in); int t; /* socket of connection */ memset(&isa, 0, sizeof(struct sockaddr_in)); err = 0; t = accept(s->s,(struct sockaddr *)&isa,&addrlen); if (t < 0) { break; } if (s->localhost_only && !ipv4_is_loopback(isa.sin_addr)) { close(t); /* someone let nonlocal through?! */ } else if (plug_accepting(s->plug, (void*)t)) { close(t); /* denied or error */ } break; } /* * If we reach here, this is not a listening socket, so * readability really means readability. */ /* In the case the socket is still frozen, we don't even bother */ if (s->frozen) { s->frozen_readable = 1; break; } /* * We have received data on the socket. For an oobinline * socket, this might be data _before_ an urgent pointer, * in which case we send it to the back end with type==1 * (data prior to urgent). */ if (s->oobinline && s->oobpending) { atmark = 1; if (ioctl(s->s, SIOCATMARK, &atmark) == 0 && atmark) s->oobpending = FALSE; /* clear this indicator */ } else atmark = 1; ret = recv(s->s, buf, s->oobpending ? 1 : sizeof(buf), 0); noise_ultralight(ret); if (ret < 0) { if (errno == EWOULDBLOCK) { break; } } if (ret < 0) { return plug_closing(s->plug, error_string(errno), errno, 0); } else if (0 == ret) { return plug_closing(s->plug, NULL, 0, 0); } else { return plug_receive(s->plug, atmark ? 0 : 1, buf, ret); } break; case 2: /* writable */ if (!s->connected) { /* * select() reports a socket as _writable_ when an * asynchronous connection is completed. */ s->connected = s->writable = 1; uxsel_tell(s); break; } else { int bufsize_before, bufsize_after; s->writable = 1; bufsize_before = s->sending_oob + bufchain_size(&s->output_data); try_send(s); bufsize_after = s->sending_oob + bufchain_size(&s->output_data); if (bufsize_after < bufsize_before) plug_sent(s->plug, bufsize_after); } break; } return 1; } /* * Deal with socket errors detected in try_send(). */ void net_pending_errors(void) { int i; Actual_Socket s; /* * This might be a fiddly business, because it's just possible * that handling a pending error on one socket might cause * others to be closed. (I can't think of any reason this might * happen in current SSH implementation, but to maintain * generality of this network layer I'll assume the worst.) * * So what we'll do is search the socket list for _one_ socket * with a pending error, and then handle it, and then search * the list again _from the beginning_. Repeat until we make a * pass with no socket errors present. That way we are * protected against the socket list changing under our feet. */ do { for (i = 0; (s = index234(sktree, i)) != NULL; i++) { if (s->pending_error) { /* * An error has occurred on this socket. Pass it to the * plug. */ plug_closing(s->plug, error_string(s->pending_error), s->pending_error, 0); break; } } } while (s); } /* * Each socket abstraction contains a `void *' private field in * which the client can keep state. */ static void sk_tcp_set_private_ptr(Socket sock, void *ptr) { Actual_Socket s = (Actual_Socket) sock; s->private_ptr = ptr; } static void *sk_tcp_get_private_ptr(Socket sock) { Actual_Socket s = (Actual_Socket) sock; return s->private_ptr; } /* * Special error values are returned from sk_namelookup and sk_new * if there's a problem. These functions extract an error message, * or return NULL if there's no problem. */ char *sk_addr_error(SockAddr addr) { return addr->error; } static char *sk_tcp_socket_error(Socket sock) { Actual_Socket s = (Actual_Socket) sock; return s->error; } static void sk_tcp_set_frozen(Socket sock, int is_frozen) { Actual_Socket s = (Actual_Socket) sock; if (s->frozen == is_frozen) return; s->frozen = is_frozen; if (!is_frozen && s->frozen_readable) { char c; recv(s->s, &c, 1, MSG_PEEK); } s->frozen_readable = 0; uxsel_tell(s); } static void uxsel_tell(Actual_Socket s) { int rwx = 0; if (!s->connected) rwx |= 2; /* write == connect */ if (s->connected && !s->frozen) rwx |= 1 | 4; /* read, except */ if (bufchain_size(&s->output_data)) rwx |= 2; /* write */ if (s->listener) rwx |= 1; /* read == accept */ uxsel_set(s->s, rwx, net_select_result); } int net_service_lookup(char *service) { struct servent *se; se = getservbyname(service, NULL); if (se != NULL) return ntohs(se->s_port); else return 0; }