+/*
+ * Unix networking abstraction.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <netdb.h>
+
+#define DEFINE_PLUG_METHOD_MACROS
+#include "putty.h"
+#include "network.h"
+#include "tree234.h"
+
+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;
+ /* address family this belongs to, AF_INET for IPv4, AF_INET6 for IPv6. */
+ int family;
+ unsigned long address; /* Address IPv4 style. */
+#ifdef IPV6
+ struct addrinfo *ai; /* Address IPv6 style. */
+#endif
+};
+
+static tree234 *sktree;
+
+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)
+{
+ switch (error) {
+ case EACCES:
+ return "Network error: Permission denied";
+ case EADDRINUSE:
+ return "Network error: Address already in use";
+ case EADDRNOTAVAIL:
+ return "Network error: Cannot assign requested address";
+ case EAFNOSUPPORT:
+ return
+ "Network error: Address family not supported by protocol family";
+ case EALREADY:
+ return "Network error: Operation already in progress";
+ case ECONNABORTED:
+ return "Network error: Software caused connection abort";
+ case ECONNREFUSED:
+ return "Network error: Connection refused";
+ case ECONNRESET:
+ return "Network error: Connection reset by peer";
+ case EDESTADDRREQ:
+ return "Network error: Destination address required";
+ case EFAULT:
+ return "Network error: Bad address";
+ case EHOSTDOWN:
+ return "Network error: Host is down";
+ case EHOSTUNREACH:
+ return "Network error: No route to host";
+ case EINPROGRESS:
+ return "Network error: Operation now in progress";
+ case EINTR:
+ return "Network error: Interrupted function call";
+ case EINVAL:
+ return "Network error: Invalid argument";
+ case EISCONN:
+ return "Network error: Socket is already connected";
+ case EMFILE:
+ return "Network error: Too many open files";
+ case EMSGSIZE:
+ return "Network error: Message too long";
+ case ENETDOWN:
+ return "Network error: Network is down";
+ case ENETRESET:
+ return "Network error: Network dropped connection on reset";
+ case ENETUNREACH:
+ return "Network error: Network is unreachable";
+ case ENOBUFS:
+ return "Network error: No buffer space available";
+ case ENOPROTOOPT:
+ return "Network error: Bad protocol option";
+ case ENOTCONN:
+ return "Network error: Socket is not connected";
+ case ENOTSOCK:
+ return "Network error: Socket operation on non-socket";
+ case EOPNOTSUPP:
+ return "Network error: Operation not supported";
+ case EPFNOSUPPORT:
+ return "Network error: Protocol family not supported";
+ case EPROTONOSUPPORT:
+ return "Network error: Protocol not supported";
+ case EPROTOTYPE:
+ return "Network error: Protocol wrong type for socket";
+ case ESHUTDOWN:
+ return "Network error: Cannot send after socket shutdown";
+ case ESOCKTNOSUPPORT:
+ return "Network error: Socket type not supported";
+ case ETIMEDOUT:
+ return "Network error: Connection timed out";
+ case EWOULDBLOCK:
+ return "Network error: Resource temporarily unavailable";
+ default:
+ return "Unknown network error";
+ }
+}
+
+SockAddr sk_namelookup(char *host, char **canonicalname)
+{
+ SockAddr ret = smalloc(sizeof(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");
+ }
+
+#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 = smalloc(1+strlen(realhost));
+ strcpy(*canonicalname, realhost);
+ return ret;
+}
+
+void sk_getaddr(SockAddr addr, char *buf, int buflen)
+{
+#ifdef IPV6
+ if (addr->family == AF_INET) {
+#endif
+ struct in_addr a;
+ a.s_addr = htonl(addr->address);
+ strncpy(buf, inet_ntoa(a), buflen);
+#ifdef IPV6
+ } else {
+ FIXME; /* I don't know how to get a text form of an IPv6 address. */
+ }
+#endif
+}
+
+int sk_addrtype(SockAddr addr)
+{
+ return (addr->family == AF_INET ? ADDRTYPE_IPV4 : ADDRTYPE_IPV6);
+}
+
+void sk_addrcopy(SockAddr addr, char *buf)
+{
+#ifdef IPV6
+ if (addr->family == AF_INET) {
+#endif
+ struct in_addr a;
+ a.s_addr = htonl(addr->address);
+ memcpy(buf, (char*) &a.s_addr, 4);
+#ifdef IPV6
+ } else {
+ memcpy(buf, (char*) addr->ai, 16);
+ }
+#endif
+}
+
+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, char *data, int len);
+static int sk_tcp_write_oob(Socket s, 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);
+
+Socket sk_register(void *sock, Plug plug)
+{
+ static struct socket_function_table 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
+ };
+
+ Actual_Socket ret;
+
+ /*
+ * Create Socket structure.
+ */
+ ret = smalloc(sizeof(struct Socket_tag));
+ ret->fn = &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;
+
+ add234(sktree, ret);
+
+ return (Socket) ret;
+}
+
+Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
+ int nodelay, Plug plug)
+{
+ static struct socket_function_table 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
+ };
+
+ int s;
+#ifdef IPV6
+ struct sockaddr_in6 a6;
+#endif
+ struct sockaddr_in a;
+ int err;
+ Actual_Socket ret;
+ short localport;
+
+ /*
+ * Create Socket structure.
+ */
+ ret = smalloc(sizeof(struct Socket_tag));
+ ret->fn = &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.
+ */
+ 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);
+ }
+
+ 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) {
+ /*
+ * FIXME: We are prepared to receive EWOULDBLOCK here,
+ * because we might want the connection to be made
+ * asynchronously; but how do we actually arrange this in
+ * Unix? I forget.
+ */
+ if ( errno != EWOULDBLOCK ) {
+ 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;
+ }
+
+ add234(sktree, ret);
+
+ return (Socket) ret;
+}
+
+Socket sk_newlistener(int port, Plug plug, int local_host_only)
+{
+ static struct socket_function_table 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
+ };
+
+ 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 = smalloc(sizeof(struct Socket_tag));
+ ret->fn = &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;
+ if (local_host_only)
+ a6.sin6_addr = in6addr_loopback;
+ else
+ a6.sin6_addr = in6addr_any;
+ a6.sin6_port = htons(port);
+ } else
+#endif
+ {
+ a.sin_family = AF_INET;
+ 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;
+ }
+
+ add234(sktree, ret);
+
+ return (Socket) ret;
+}
+
+static void sk_tcp_close(Socket sock)
+{
+ Actual_Socket s = (Actual_Socket) sock;
+
+ del234(sktree, s);
+ close(s->s);
+ sfree(s);
+}
+
+/*
+ * 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);
+ }
+ }
+ }
+}
+
+static int sk_tcp_write(Socket sock, 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, 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;
+}
+
+int 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) {
+#ifdef FIXME_NONBLOCKING_CONNECTIONS
+ case FIXME: /* connected */
+ s->connected = s->writable = 1;
+ break;
+#endif
+ 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 fall through
+ * to the read case.
+ */
+ s->oobpending = TRUE;
+ 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 &&
+ ntohl(isa.sin_addr.s_addr) != INADDR_LOOPBACK) {
+ 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, 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 */
+ {
+ 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;
+}
+
+/*
+ * For Unix select()-based frontends: enumerate all sockets
+ * currently active, and state whether we currently wish to receive
+ * select events on them for reading, writing and exceptional
+ * status.
+ */
+static void set_rwx(Actual_Socket s, int *rwx)
+{
+ int val = 0;
+ if (s->connected && !s->frozen)
+ val |= 1 | 4; /* read, except */
+ if (bufchain_size(&s->output_data))
+ val |= 2; /* write */
+ if (s->listener)
+ val |= 1; /* read == accept */
+ *rwx = val;
+}
+
+int first_socket(int *state, int *rwx)
+{
+ Actual_Socket s;
+ *state = 0;
+ s = index234(sktree, (*state)++);
+ if (s)
+ set_rwx(s, rwx);
+ return s ? s->s : -1;
+}
+
+int next_socket(int *state, int *rwx)
+{
+ Actual_Socket s = index234(sktree, (*state)++);
+ if (s)
+ set_rwx(s, rwx);
+ return s ? s->s : -1;
+}
+
+int net_service_lookup(char *service)
+{
+ struct servent *se;
+ se = getservbyname(service, NULL);
+ if (se != NULL)
+ return ntohs(se->s_port);
+ else
+ return 0;
+}