1 /* $NetBSD: inet_listen.c,v 1.1.1.1 2009/06/23 10:09:00 tron Exp $ */ 2 3 /*++ 4 /* NAME 5 /* inet_listen 3 6 /* SUMMARY 7 /* start TCP listener 8 /* SYNOPSIS 9 /* #include <listen.h> 10 /* 11 /* int inet_windowsize; 12 /* 13 /* int inet_listen(addr, backlog, block_mode) 14 /* const char *addr; 15 /* int backlog; 16 /* int block_mode; 17 /* 18 /* int inet_accept(fd) 19 /* int fd; 20 /* DESCRIPTION 21 /* The \fBinet_listen\fR routine starts a TCP listener 22 /* on the specified address, with the specified backlog, and returns 23 /* the resulting file descriptor. 24 /* 25 /* inet_accept() accepts a connection and sanitizes error results. 26 /* 27 /* Specify an inet_windowsize value > 0 to override the TCP 28 /* window size that the server advertises to the client. 29 /* 30 /* Arguments: 31 /* .IP addr 32 /* The communication endpoint to listen on. The syntax is "host:port". 33 /* Host and port may be specified in symbolic form or numerically. 34 /* A null host field means listen on all network interfaces. 35 /* .IP backlog 36 /* This argument is passed on to the \fIlisten(2)\fR routine. 37 /* .IP block_mode 38 /* Either NON_BLOCKING for a non-blocking socket, or BLOCKING for 39 /* blocking mode. 40 /* .IP fd 41 /* File descriptor returned by inet_listen(). 42 /* DIAGNOSTICS 43 /* Fatal errors: inet_listen() aborts upon any system call failure. 44 /* inet_accept() leaves all error handling up to the caller. 45 /* LICENSE 46 /* .ad 47 /* .fi 48 /* The Secure Mailer license must be distributed with this software. 49 /* AUTHOR(S) 50 /* Wietse Venema 51 /* IBM T.J. Watson Research 52 /* P.O. Box 704 53 /* Yorktown Heights, NY 10598, USA 54 /*--*/ 55 56 /* System libraries. */ 57 58 #include <sys_defs.h> 59 #include <sys/socket.h> 60 #include <netinet/in.h> 61 #include <arpa/inet.h> 62 #include <netdb.h> 63 #ifndef MAXHOSTNAMELEN 64 #include <sys/param.h> 65 #endif 66 #include <errno.h> 67 #include <string.h> 68 #include <unistd.h> 69 70 /* Utility library. */ 71 72 #include "mymalloc.h" 73 #include "msg.h" 74 #include "host_port.h" 75 #include "iostuff.h" 76 #include "listen.h" 77 #include "sane_accept.h" 78 #include "myaddrinfo.h" 79 #include "sock_addr.h" 80 #include "inet_proto.h" 81 82 /* inet_listen - create TCP listener */ 83 84 int inet_listen(const char *addr, int backlog, int block_mode) 85 { 86 struct addrinfo *res; 87 struct addrinfo *res0; 88 int aierr; 89 int sock; 90 int on = 1; 91 char *buf; 92 char *host; 93 char *port; 94 const char *parse_err; 95 MAI_HOSTADDR_STR hostaddr; 96 MAI_SERVPORT_STR portnum; 97 INET_PROTO_INFO *proto_info; 98 99 /* 100 * Translate address information to internal form. 101 */ 102 buf = mystrdup(addr); 103 if ((parse_err = host_port(buf, &host, "", &port, (char *) 0)) != 0) 104 msg_fatal("%s: %s", addr, parse_err); 105 if (*host == 0) 106 host = 0; 107 if ((aierr = hostname_to_sockaddr(host, port, SOCK_STREAM, &res0)) != 0) 108 msg_fatal("%s: %s", addr, MAI_STRERROR(aierr)); 109 myfree(buf); 110 /* No early returns or res0 leaks. */ 111 112 proto_info = inet_proto_info(); 113 for (res = res0; /* see below */ ; res = res->ai_next) { 114 115 /* 116 * No usable address found. 117 */ 118 if (res == 0) 119 msg_fatal("%s: host found but no usable address", addr); 120 121 /* 122 * Safety net. 123 */ 124 if (strchr((char *) proto_info->sa_family_list, res->ai_family) != 0) 125 break; 126 127 msg_info("skipping address family %d for %s", res->ai_family, addr); 128 } 129 130 /* 131 * Show what address we're trying. 132 */ 133 if (msg_verbose) { 134 SOCKADDR_TO_HOSTADDR(res->ai_addr, res->ai_addrlen, 135 &hostaddr, &portnum, 0); 136 msg_info("trying... [%s]:%s", hostaddr.buf, portnum.buf); 137 } 138 139 /* 140 * Create a listener socket. 141 */ 142 if ((sock = socket(res->ai_family, res->ai_socktype, 0)) < 0) 143 msg_fatal("socket: %m"); 144 #ifdef HAS_IPV6 145 # if defined(IPV6_V6ONLY) && !defined(BROKEN_AI_PASSIVE_NULL_HOST) 146 if (res->ai_family == AF_INET6 147 && setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, 148 (char *) &on, sizeof(on)) < 0) 149 msg_fatal("setsockopt(IPV6_V6ONLY): %m"); 150 # endif 151 #endif 152 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, 153 (char *) &on, sizeof(on)) < 0) 154 msg_fatal("setsockopt(SO_REUSEADDR): %m"); 155 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) { 156 SOCKADDR_TO_HOSTADDR(res->ai_addr, res->ai_addrlen, 157 &hostaddr, &portnum, 0); 158 msg_fatal("bind %s port %s: %m", hostaddr.buf, portnum.buf); 159 } 160 freeaddrinfo(res0); 161 non_blocking(sock, block_mode); 162 if (inet_windowsize > 0) 163 set_inet_windowsize(sock, inet_windowsize); 164 if (listen(sock, backlog) < 0) 165 msg_fatal("listen: %m"); 166 return (sock); 167 } 168 169 /* inet_accept - accept connection */ 170 171 int inet_accept(int fd) 172 { 173 struct sockaddr_storage ss; 174 SOCKADDR_SIZE ss_len = sizeof(ss); 175 176 return (sane_accept(fd, (struct sockaddr *) & ss, &ss_len)); 177 } 178