X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/1f0fa9318a11ebb622fc9d7fc6d004aaba32fa7c..d1d15050454d0d8a43726f05048fda0380a54c01:/socket.c diff --git a/socket.c b/socket.c index 0595dc22..8a54911f 100644 --- a/socket.c +++ b/socket.c @@ -1,7 +1,9 @@ /* -*- c-file-style: "linux" -*- + rsync -- fast file replication program + Copyright (C) 1992-2001 by Andrew Tridgell - Copyright (C) 2001 by Martin Pool + Copyright (C) 2001, 2002 by Martin Pool This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -18,19 +20,19 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ -/* - socket functions used in rsync - - */ +/** + * @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" -#ifndef HAVE_GETADDRINFO -#include "lib/addrinfo.h" -#endif - -extern int af; - /* 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) @@ -95,20 +97,66 @@ static int establish_proxy_connection(int fd, char *host, int port) } +/** + * 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 . +/** + * Open a socket to a tcp remote host with the specified port . * - * Based on code from Warren. Proxy support by Stephen Rothwell + * 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. * - * @param bind_address Local address to use. Normally NULL to get the stack default. + * 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 open_socket_out(char *host, int port, const char *bind_address, + int af_hint) { int type = SOCK_STREAM; int error; int s; - int result; struct addrinfo hints, *res0, *res; char portbuf[10]; char *h; @@ -139,41 +187,32 @@ int open_socket_out(char *host, int port, const char *bind_address) } memset(&hints, 0, sizeof(hints)); - hints.ai_family = af; + hints.ai_family = af_hint; hints.ai_socktype = type; error = getaddrinfo(h, portbuf, &hints, &res0); if (error) { - rprintf(FERROR, RSYNC_NAME ": getaddrinfo: %s: %s\n", portbuf, gai_strerror(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) { - struct addrinfo bhints, *bres; - - memset(&bhints, 0, sizeof(bhints)); - bhints.ai_family = res->ai_family; - bhints.ai_socktype = type; - bhints.ai_flags = AI_PASSIVE; - error = getaddrinfo(bind_address, NULL, &bhints, &bres); - if (error) { - rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n", - bind_address, gai_strerror(error)); - continue; - } - if (bres->ai_next) { - rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s resolved to multiple hosts\n", - bind_address); - freeaddrinfo(bres); + if (bind_address) + if (try_bind_local(s, res->ai_family, type, + bind_address) == -1) { + close(s); + s = -1; continue; } - bind(s, bres->ai_addr, bres->ai_addrlen); - } if (connect(s, res->ai_addr, res->ai_addrlen) < 0) { close(s); @@ -212,14 +251,16 @@ int open_socket_out(char *host, int port, const char *bind_address) **/ int open_socket_out_wrapped (char *host, int port, - const char *bind_address) + 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); + return open_socket_out (host, port, bind_address, + af_hint); } @@ -227,55 +268,73 @@ int open_socket_out_wrapped (char *host, /** * 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) +static int open_socket_in(int type, int port, const char *bind_address, + int af_hint) { int one=1; int s; - struct addrinfo hints, *res; + struct addrinfo hints, *all_ai, *resp; char portbuf[10]; int error; memset(&hints, 0, sizeof(hints)); - hints.ai_family = af; + 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, &res); + 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; } - if (res->ai_next) { - rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: " - "resolved to multiple hosts\n", - bind_address); - freeaddrinfo(res); - return -1; - } - s = socket(res->ai_family, res->ai_socktype, res->ai_protocol); - if (s < 0) { - rprintf(FERROR, RSYNC_NAME ": open socket in failed: %s\n", - strerror(errno)); - freeaddrinfo(res); - 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); - setsockopt(s,SOL_SOCKET,SO_REUSEADDR,(char *)&one,sizeof(one)); - - /* now we've got a socket - we need to bind it */ - if (bind(s, res->ai_addr, res->ai_addrlen) < 0) { - rprintf(FERROR, RSYNC_NAME ": bind failed on port %d\n", port); - freeaddrinfo(res); - close(s); - return -1; + 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; } - return s; + rprintf(FERROR, RSYNC_NAME ": open inbound socket on port %d failed: " + "%s\n", + port, + strerror(errno)); + + freeaddrinfo(all_ai); + return -1; } @@ -309,9 +368,10 @@ void start_accept_loop(int port, int (*fn)(int )) { int s; extern char *bind_address; + extern int default_af_hint; /* open an incoming socket */ - s = open_socket_in(SOCK_STREAM, port, bind_address); + s = open_socket_in(SOCK_STREAM, port, bind_address, default_af_hint); if (s == -1) exit_cleanup(RERR_SOCKETIO); @@ -327,8 +387,8 @@ void start_accept_loop(int port, int (*fn)(int )) while (1) { fd_set fds; int fd; - struct sockaddr addr; - int in_addrlen = sizeof(addr); + struct sockaddr_storage addr; + socklen_t addrlen = sizeof addr; /* close log file before the potentially very long select so file can be trimmed by another process instead of growing @@ -344,7 +404,7 @@ void start_accept_loop(int port, int (*fn)(int )) if(!FD_ISSET(s, &fds)) continue; - fd = accept(s,(struct sockaddr *)&addr,&in_addrlen); + fd = accept(s,(struct sockaddr *)&addr,&addrlen); if (fd == -1) continue; @@ -510,8 +570,8 @@ void become_daemon(void) **/ char *client_addr(int fd) { - struct sockaddr ss; - int length = sizeof(ss); + struct sockaddr_storage ss; + socklen_t length = sizeof ss; static char addr_buf[100]; static int initialised; @@ -519,23 +579,32 @@ char *client_addr(int fd) initialised = 1; - if (getpeername(fd, &ss, &length)) { + if (getpeername(fd, (struct sockaddr *)&ss, &length)) { exit_cleanup(RERR_SOCKETIO); } - getnameinfo(&ss, length, + getnameinfo((struct sockaddr *)&ss, length, addr_buf, sizeof(addr_buf), NULL, 0, NI_NUMERICHOST); return addr_buf; } +static int get_sockaddr_family(const struct sockaddr_storage *ss) +{ + return ((struct sockaddr *) ss)->sa_family; +} + + /** - * Return the DNS name of the client + * Return the DNS name of the client. + * + * The name is statically cached so that repeated lookups are quick, + * so there is a limit of one lookup per customer. **/ char *client_name(int fd) { - struct sockaddr ss; - int length = sizeof(ss); + struct sockaddr_storage ss; + socklen_t length = sizeof ss; static char name_buf[100]; static char port_buf[100]; char *def = "UNKNOWN"; @@ -550,12 +619,21 @@ char *client_name(int fd) strcpy(name_buf,def); if (getpeername(fd, (struct sockaddr *)&ss, &length)) { + /* FIXME: Can we really not continue? */ + rprintf(FERROR, RSYNC_NAME ": getpeername on fd%d failed: %s\n", + fd, strerror(errno)); exit_cleanup(RERR_SOCKETIO); } #ifdef INET6 - if (ss.ss_family == AF_INET6 && + if (get_sockaddr_family(&ss) == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&ss)->sin6_addr)) { + /* OK, so ss is in the IPv6 family, but it is really + * an IPv4 address: something like + * "::ffff:10.130.1.2". If we use it as-is, then the + * reverse lookup might fail or perhaps something else + * bad might happen. So instead we convert it to an + * equivalent address in the IPv4 address family. */ struct sockaddr_in6 sin6; struct sockaddr_in *sin; @@ -568,6 +646,9 @@ char *client_name(int fd) sin->sin_len = length; #endif sin->sin_port = sin6.sin6_port; + /* FIXME: Isn't there a macro we can use here rather + * than grovelling through the struct? It might be + * wrong on some systems. */ memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12], sizeof(sin->sin_addr)); } @@ -598,7 +679,7 @@ char *client_name(int fd) /* XXX sin6_flowinfo and other fields */ for (res = res0; res; res = res->ai_next) { - if (res->ai_family != ss.sa_family) + if (res->ai_family != get_sockaddr_family(&ss)) continue; if (res->ai_addrlen != length) continue; @@ -606,81 +687,17 @@ char *client_name(int fd) break; } - /* TODO: Do a forward lookup as well to prevent spoofing */ - if (res == NULL) { strcpy(name_buf, def); - rprintf(FERROR, - "reverse name lookup mismatch - spoofed address?\n"); + rprintf(FERROR, RSYNC_NAME ": " + "reverse name lookup for \"%s\" failed on fd%d - spoofed address? \n", + name_buf, fd); } freeaddrinfo(res0); return name_buf; } -/** - * Convert a string to an IP address. The string can be a name or - * dotted decimal number. - * - * Returns a pointer to a static in_addr struct -- if you call this - * more than once then you should copy it. - * - * TODO: Use getaddrinfo() instead, or make this function call getnameinfo - **/ -struct in_addr *ip_address(const char *str) -{ - static struct in_addr ret; - struct hostent *hp; - - if (!str) { - rprintf (FERROR, "ip_address received NULL name\n"); - return NULL; - } - - /* try as an IP address */ - if (inet_aton(str, &ret) != 0) { - return &ret; - } - - /* otherwise assume it's a network name of some sort and use - gethostbyname */ - if ((hp = gethostbyname (str)) == 0) { - rprintf(FERROR, "gethostbyname failed for \"%s\": unknown host?\n",str); - return NULL; - } - - if (hp->h_addr == NULL) { - rprintf(FERROR, "gethostbyname: host address is invalid for host \"%s\"\n",str); - return NULL; - } - - if (hp->h_length > sizeof ret) { - rprintf(FERROR, "gethostbyname: host address for \"%s\" is too large\n", - str); - return NULL; - } - - if (hp->h_addrtype != AF_INET) { - rprintf (FERROR, "gethostname: host address for \"%s\" is not IPv4\n", - str); - return NULL; - } - - /* This is kind of difficult. The only field in ret is - s_addr, which is the IP address as a 32-bit int. On - UNICOS, s_addr is in fact a *bitfield* for reasons best - know to Cray. This means we can't memcpy in to it. On the - other hand, h_addr is a char*, so we can't just assign. - - Since there's meant to be only one field inside the in_addr - structure we will try just copying over the top and see how - that goes. */ - memcpy (&ret, hp->h_addr, hp->h_length); - - return &ret; -} - - /******************************************************************* this is like socketpair but uses tcp. It is used by the Samba