1/* $NetBSD: inet_listen.c,v 1.3 2022/10/08 16:12:50 christos 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/* Wietse Venema 56/* Google, Inc. 57/* 111 8th Avenue 58/* New York, NY 10011, USA 59/*--*/ 60 61/* System libraries. */ 62 63#include <sys_defs.h> 64#include <sys/socket.h> 65#include <netinet/in.h> 66#include <arpa/inet.h> 67#include <netdb.h> 68#ifndef MAXHOSTNAMELEN 69#include <sys/param.h> 70#endif 71#include <errno.h> 72#include <string.h> 73#include <unistd.h> 74 75/* Utility library. */ 76 77#include "mymalloc.h" 78#include "msg.h" 79#include "host_port.h" 80#include "iostuff.h" 81#include "listen.h" 82#include "sane_accept.h" 83#include "myaddrinfo.h" 84#include "sock_addr.h" 85#include "inet_proto.h" 86 87/* inet_listen - create TCP listener */ 88 89int inet_listen(const char *addr, int backlog, int block_mode) 90{ 91 struct addrinfo *res; 92 struct addrinfo *res0; 93 int aierr; 94 int sock; 95 int on = 1; 96 char *buf; 97 char *host; 98 char *port; 99 const char *parse_err; 100 MAI_HOSTADDR_STR hostaddr; 101 MAI_SERVPORT_STR portnum; 102 const INET_PROTO_INFO *proto_info; 103 104 /* 105 * Translate address information to internal form. 106 */ 107 buf = mystrdup(addr); 108 if ((parse_err = host_port(buf, &host, "", &port, (char *) 0)) != 0) 109 msg_fatal("%s: %s", addr, parse_err); 110 if (*host == 0) 111 host = 0; 112 if ((aierr = hostname_to_sockaddr(host, port, SOCK_STREAM, &res0)) != 0) 113 msg_fatal("%s: %s", addr, MAI_STRERROR(aierr)); 114 myfree(buf); 115 /* No early returns or res0 leaks. */ 116 117 proto_info = inet_proto_info(); 118 for (res = res0; /* see below */ ; res = res->ai_next) { 119 120 /* 121 * No usable address found. 122 */ 123 if (res == 0) 124 msg_fatal("%s: host found but no usable address", addr); 125 126 /* 127 * Safety net. 128 */ 129 if (strchr((char *) proto_info->sa_family_list, res->ai_family) != 0) 130 break; 131 132 msg_info("skipping address family %d for %s", res->ai_family, addr); 133 } 134 135 /* 136 * Show what address we're trying. 137 */ 138 if (msg_verbose) { 139 SOCKADDR_TO_HOSTADDR(res->ai_addr, res->ai_addrlen, 140 &hostaddr, &portnum, 0); 141 msg_info("trying... [%s]:%s", hostaddr.buf, portnum.buf); 142 } 143 144 /* 145 * Create a listener socket. 146 */ 147 if ((sock = socket(res->ai_family, res->ai_socktype, 0)) < 0) 148 msg_fatal("socket: %m"); 149#ifdef HAS_IPV6 150#if defined(IPV6_V6ONLY) && !defined(BROKEN_AI_PASSIVE_NULL_HOST) 151 if (res->ai_family == AF_INET6 152 && setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, 153 (void *) &on, sizeof(on)) < 0) 154 msg_fatal("setsockopt(IPV6_V6ONLY): %m"); 155#endif 156#endif 157 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, 158 (void *) &on, sizeof(on)) < 0) 159 msg_fatal("setsockopt(SO_REUSEADDR): %m"); 160#if defined(SO_REUSEPORT_LB) 161 if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT_LB, 162 (void *) &on, sizeof(on)) < 0) 163 msg_fatal("setsockopt(SO_REUSEPORT_LB): %m"); 164#elif defined(SO_REUSEPORT) 165 if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, 166 (void *) &on, sizeof(on)) < 0) 167 msg_fatal("setsockopt(SO_REUSEPORT): %m"); 168#endif 169 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) { 170 SOCKADDR_TO_HOSTADDR(res->ai_addr, res->ai_addrlen, 171 &hostaddr, &portnum, 0); 172 msg_fatal("bind %s port %s: %m", hostaddr.buf, portnum.buf); 173 } 174 freeaddrinfo(res0); 175 non_blocking(sock, block_mode); 176 if (inet_windowsize > 0) 177 set_inet_windowsize(sock, inet_windowsize); 178 if (listen(sock, backlog) < 0) 179 msg_fatal("listen: %m"); 180 return (sock); 181} 182 183/* inet_accept - accept connection */ 184 185int inet_accept(int fd) 186{ 187 struct sockaddr_storage ss; 188 SOCKADDR_SIZE ss_len = sizeof(ss); 189 190 return (sane_accept(fd, (struct sockaddr *) &ss, &ss_len)); 191} 192