+/**
+ * @file socket.c
+ *
+ * Socket functions used in rsync.
+ *
+ * This file is now converted to use the new-style getaddrinfo()
+ * interface, which supports IPv6 but is also supported on recent
+ * IPv4-only machines. On systems that don't have that interface, we
+ * emulate it using the KAME implementation.
+ **/
+
+#include "rsync.h"
+
+
+/* Establish a proxy connection on an open socket to a web roxy by
+ * using the CONNECT method. */
+static int establish_proxy_connection(int fd, char *host, int port)
+{
+ char buffer[1024];
+ char *cp;
+
+ snprintf(buffer, sizeof(buffer), "CONNECT %s:%d HTTP/1.0\r\n\r\n", host, port);
+ if (write(fd, buffer, strlen(buffer)) != (int) strlen(buffer)) {
+ rprintf(FERROR, "failed to write to proxy: %s\n",
+ strerror(errno));
+ return -1;
+ }
+
+ for (cp = buffer; cp < &buffer[sizeof(buffer) - 1]; cp++) {
+ if (read(fd, cp, 1) != 1) {
+ rprintf(FERROR, "failed to read from proxy: %s\n",
+ strerror(errno));
+ return -1;
+ }
+ if (*cp == '\n')
+ break;
+ }
+
+ if (*cp != '\n')
+ cp++;
+ *cp-- = '\0';
+ if (*cp == '\r')
+ *cp = '\0';
+ if (strncmp(buffer, "HTTP/", 5) != 0) {
+ rprintf(FERROR, "bad response from proxy - %s\n",
+ buffer);
+ return -1;
+ }
+ for (cp = &buffer[5]; isdigit(*cp) || (*cp == '.'); cp++)
+ ;
+ while (*cp == ' ')
+ cp++;
+ if (*cp != '2') {
+ rprintf(FERROR, "bad response from proxy - %s\n",
+ buffer);
+ return -1;
+ }
+ /* throw away the rest of the HTTP header */
+ while (1) {
+ for (cp = buffer; cp < &buffer[sizeof(buffer) - 1];
+ cp++) {
+ if (read(fd, cp, 1) != 1) {
+ rprintf(FERROR, "failed to read from proxy: %s\n",
+ strerror(errno));
+ return -1;
+ }
+ if (*cp == '\n')
+ break;
+ }
+ if ((cp > buffer) && (*cp == '\n'))
+ cp--;
+ if ((cp == buffer) && ((*cp == '\n') || (*cp == '\r')))
+ break;
+ }
+ return 0;
+}
+
+
+/**
+ * Try to set the local address for a newly-created socket. Return -1
+ * if this fails.
+ **/
+int try_bind_local(int s,
+ int ai_family, int ai_socktype,
+ const char *bind_address)
+{
+ int error;
+ struct addrinfo bhints, *bres_all, *r;
+
+ memset(&bhints, 0, sizeof(bhints));
+ bhints.ai_family = ai_family;
+ bhints.ai_socktype = ai_socktype;
+ bhints.ai_flags = AI_PASSIVE;
+ if ((error = getaddrinfo(bind_address, NULL, &bhints, &bres_all))) {
+ rprintf(FERROR, RSYNC_NAME ": getaddrinfo %s: %s\n",
+ bind_address, gai_strerror(error));
+ return -1;
+ }
+
+ for (r = bres_all; r; r = r->ai_next) {
+ if (bind(s, r->ai_addr, r->ai_addrlen) == -1)
+ continue;
+ return s;
+ }
+
+ /* no error message; there might be some problem that allows
+ * creation of the socket but not binding, perhaps if the
+ * machine has no ipv6 address of this name. */
+ return -1;
+}
+
+
+/**
+ * Open a socket to a tcp remote host with the specified port .
+ *
+ * Based on code from Warren. Proxy support by Stephen Rothwell.
+ * getaddrinfo() rewrite contributed by KAME.net.
+ *
+ * Now that we support IPv6 we need to look up the remote machine's
+ * address first, using @p af_hint to set a preference for the type
+ * of address. Then depending on whether it has v4 or v6 addresses we
+ * try to open a connection.
+ *
+ * The loop allows for machines with some addresses which may not be
+ * reachable, perhaps because we can't e.g. route ipv6 to that network
+ * but we can get ip4 packets through.
+ *
+ * @param bind_address Local address to use. Normally NULL to bind
+ * the wildcard address.
+ *
+ * @param af_hint Address family, e.g. AF_INET or AF_INET6.
+ **/
+int open_socket_out(char *host, int port, const char *bind_address,
+ int af_hint)
+{
+ int type = SOCK_STREAM;
+ int error;
+ int s;
+ struct addrinfo hints, *res0, *res;
+ char portbuf[10];
+ char *h;
+ int proxied = 0;
+ char buffer[1024];
+ char *cp;
+
+ /* if we have a RSYNC_PROXY env variable then redirect our
+ * connetcion via a web proxy at the given address. The format
+ * is hostname:port */
+ h = getenv("RSYNC_PROXY");
+ proxied = (h != NULL) && (*h != '\0');
+
+ if (proxied) {
+ strlcpy(buffer, h, sizeof(buffer));
+ cp = strchr(buffer, ':');
+ if (cp == NULL) {
+ rprintf(FERROR,
+ "invalid proxy specification: should be HOST:PORT\n");
+ return -1;
+ }
+ *cp++ = '\0';
+ strcpy(portbuf, cp);
+ h = buffer;
+ } else {
+ snprintf(portbuf, sizeof(portbuf), "%d", port);
+ h = host;
+ }
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = af_hint;
+ hints.ai_socktype = type;
+ error = getaddrinfo(h, portbuf, &hints, &res0);
+ if (error) {
+ rprintf(FERROR, RSYNC_NAME ": getaddrinfo: %s %s: %s\n",
+ h, portbuf, gai_strerror(error));
+ return -1;
+ }
+
+ s = -1;
+ /* Try to connect to all addresses for this machine until we get
+ * through. It might e.g. be multi-homed, or have both IPv4 and IPv6
+ * addresses. We need to create a socket for each record, since the
+ * address record tells us what protocol to use to try to connect. */
+ for (res = res0; res; res = res->ai_next) {
+ s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
+ if (s < 0)
+ continue;
+
+ if (bind_address)
+ if (try_bind_local(s, res->ai_family, type,
+ bind_address) == -1) {
+ close(s);
+ s = -1;
+ continue;
+ }
+
+ if (connect(s, res->ai_addr, res->ai_addrlen) < 0) {
+ close(s);
+ s = -1;
+ continue;
+ }
+ if (proxied &&
+ establish_proxy_connection(s, host, port) != 0) {
+ close(s);
+ s = -1;
+ continue;
+ } else
+ break;
+ }
+ freeaddrinfo(res0);
+ if (s < 0) {
+ rprintf(FERROR, RSYNC_NAME ": failed to connect to %s: %s\n",
+ h, strerror(errno));
+ return -1;
+ }
+ return s;
+}
+
+
+/**
+ * Open an outgoing socket, but allow for it to be intercepted by
+ * $RSYNC_CONNECT_PROG, which will execute a program across a TCP
+ * socketpair rather than really opening a socket.
+ *
+ * We use this primarily in testing to detect TCP flow bugs, but not
+ * cause security problems by really opening remote connections.
+ *
+ * This is based on the Samba LIBSMB_PROG feature.
+ *
+ * @param bind_address Local address to use. Normally NULL to get the stack default.
+ **/
+int open_socket_out_wrapped (char *host,
+ int port,
+ const char *bind_address,
+ int af_hint)
+{
+ char *prog;
+
+ if ((prog = getenv ("RSYNC_CONNECT_PROG")) != NULL)
+ return sock_exec (prog);
+ else
+ return open_socket_out (host, port, bind_address,
+ af_hint);
+}
+
+
+
+/**
+ * Open a socket of the specified type, port and address for incoming data
+ *
+ * Try to be better about handling the results of getaddrinfo(): when
+ * opening an inbound socket, we might get several address results,
+ * e.g. for the machine's ipv4 and ipv6 name.
+ *
+ * If binding a wildcard, then any one of them should do. If an address
+ * was specified but it's insufficiently specific then that's not our
+ * fault.
+ *
+ * However, some of the advertized addresses may not work because e.g. we
+ * don't have IPv6 support in the kernel. In that case go on and try all
+ * addresses until one succeeds.
+ *
+ * @param bind_address Local address to bind, or NULL to allow it to
+ * default.
+ **/
+static int open_socket_in(int type, int port, const char *bind_address,
+ int af_hint)
+{
+ int one=1;
+ int s;
+ struct addrinfo hints, *all_ai, *resp;
+ char portbuf[10];
+ int error;
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = af_hint;
+ hints.ai_socktype = type;
+ hints.ai_flags = AI_PASSIVE;
+ snprintf(portbuf, sizeof(portbuf), "%d", port);
+ error = getaddrinfo(bind_address, portbuf, &hints, &all_ai);
+ if (error) {
+ rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n",
+ bind_address, gai_strerror(error));
+ return -1;
+ }
+
+ /* We may not be able to create the socket, if for example the
+ * machine knows about IPv6 in the C library, but not in the
+ * kernel. */
+ for (resp = all_ai; resp; resp = resp->ai_next) {
+ s = socket(resp->ai_family, resp->ai_socktype,
+ resp->ai_protocol);
+
+ if (s == -1)
+ /* See if there's another address that will work... */
+ continue;
+
+ setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
+ (char *)&one, sizeof one);
+
+ /* now we've got a socket - we need to bind it */
+ if (bind(s, all_ai->ai_addr, all_ai->ai_addrlen) < 0) {
+ /* Nope, try another */
+ close(s);
+ continue;
+ }
+
+ return s;
+ }
+
+ rprintf(FERROR, RSYNC_NAME ": open inbound socket on port %d failed: "
+ "%s\n",
+ port,
+ strerror(errno));
+
+ freeaddrinfo(all_ai);
+ return -1;
+}
+
+