/* $Id: udp.c $ */ /** @file * NAT - UDP protocol. */ /* * Copyright (C) 2006-2023 Oracle and/or its affiliates. * * This file is part of VirtualBox base platform packages, as * available from https://www.virtualbox.org. * * 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 the Free Software Foundation, in version 3 of the * License. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . * * SPDX-License-Identifier: GPL-3.0-only */ /* * This code is based on: * * Copyright (c) 1982, 1986, 1988, 1990, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)udp_usrreq.c 8.4 (Berkeley) 1/21/94 * udp_usrreq.c,v 1.4 1994/10/02 17:48:45 phk Exp */ /* * Changes and additions relating to SLiRP * Copyright (c) 1995 Danny Gasparovski. * * Please read the file COPYRIGHT for the * terms and conditions of the copyright. */ #include #include "ip_icmp.h" /* * UDP protocol implementation. * Per RFC 768, August, 1980. */ #define udpcksum 1 void udp_init(PNATState pData) { udp_last_so = &udb; udb.so_next = udb.so_prev = &udb; } /* m->m_data points at ip packet header * m->m_len length ip packet * ip->ip_len length data (IPDU) */ void udp_input(PNATState pData, register struct mbuf *m, int iphlen) { register struct ip *ip; register struct udphdr *uh; int len; struct ip save_ip; struct socket *so; int ret; int ttl, tos; LogFlowFunc(("ENTER: m = %p, iphlen = %d\n", m, iphlen)); ip = mtod(m, struct ip *); Log2(("%RTnaipv4 iphlen = %d\n", ip->ip_dst, iphlen)); udpstat.udps_ipackets++; /* * Strip IP options, if any; should skip this, * make available to user, and use on returned packets, * but we don't yet have a way to check the checksum * with options still present. */ if (iphlen > sizeof(struct ip)) { ip_stripoptions(m, (struct mbuf *)0); iphlen = sizeof(struct ip); } /* * Get IP and UDP header together in first mbuf. */ ip = mtod(m, struct ip *); uh = (struct udphdr *)((caddr_t)ip + iphlen); /* * Make mbuf data length reflect UDP length. * If not enough data to reflect UDP length, drop. */ len = RT_N2H_U16((u_int16_t)uh->uh_ulen); Assert(ip->ip_len + iphlen == (ssize_t)m_length(m, NULL)); if (ip->ip_len != len) { if (len > ip->ip_len) { udpstat.udps_badlen++; Log3(("NAT: IP(id: %hd) has bad size\n", ip->ip_id)); goto bad_free_mbuf; } m_adj(m, len - ip->ip_len); ip->ip_len = len; } /* * Save a copy of the IP header in case we want restore it * for sending an ICMP error message in response. */ save_ip = *ip; save_ip.ip_len+= iphlen; /* tcp_input subtracts this */ /* * Checksum extended UDP header and data. */ if (udpcksum && uh->uh_sum) { memset(((struct ipovly *)ip)->ih_x1, 0, 9); ((struct ipovly *)ip)->ih_len = uh->uh_ulen; #if 0 /* keep uh_sum for ICMP reply */ uh->uh_sum = cksum(m, len + sizeof (struct ip)); if (uh->uh_sum) { #endif if (cksum(m, len + iphlen)) { udpstat.udps_badsum++; Log3(("NAT: IP(id: %hd) has bad (udp) cksum\n", ip->ip_id)); goto bad_free_mbuf; } } #if 0 } #endif /* * handle DHCP/BOOTP */ if (uh->uh_dport == RT_H2N_U16_C(BOOTP_SERVER)) { bootp_input(pData, m); goto done_free_mbuf; } LogFunc(("uh src: %RTnaipv4:%d, dst: %RTnaipv4:%d\n", ip->ip_src.s_addr, RT_N2H_U16(uh->uh_sport), ip->ip_dst.s_addr, RT_N2H_U16(uh->uh_dport))); /* * handle DNS host resolver without creating a socket */ if ( pData->fUseHostResolver && uh->uh_dport == RT_H2N_U16_C(53) && CTL_CHECK(ip->ip_dst.s_addr, CTL_DNS)) { struct sockaddr_in dst, src; src.sin_addr.s_addr = ip->ip_dst.s_addr; src.sin_port = uh->uh_dport; dst.sin_addr.s_addr = ip->ip_src.s_addr; dst.sin_port = uh->uh_sport; m_adj(m, sizeof(struct udpiphdr)); m = hostresolver(pData, m, ip->ip_src.s_addr, uh->uh_sport); if (m == NULL) goto done_free_mbuf; slirpMbufTagService(pData, m, CTL_DNS); udp_output2(pData, NULL, m, &src, &dst, IPTOS_LOWDELAY); LogFlowFuncLeave(); return; } /* * handle TFTP */ if ( uh->uh_dport == RT_H2N_U16_C(TFTP_SERVER) && CTL_CHECK(ip->ip_dst.s_addr, CTL_TFTP)) { if (pData->pvTftpSessions) slirpTftpInput(pData, m); goto done_free_mbuf; } /* * XXX: DNS proxy currently relies on the fact that each socket * only serves one request. */ if ( pData->fUseDnsProxy && CTL_CHECK(ip->ip_dst.s_addr, CTL_DNS) && (uh->uh_dport == RT_H2N_U16_C(53))) { so = NULL; goto new_socket; } /* * Drop UDP packets destind for CTL_ALIAS (i.e. the hosts loopback interface) * if it is disabled. */ if ( CTL_CHECK(ip->ip_dst.s_addr, CTL_ALIAS) && !pData->fLocalhostReachable) goto done_free_mbuf; /* * Locate pcb for datagram. */ so = udp_last_so; if ( so->so_lport != uh->uh_sport || so->so_laddr.s_addr != ip->ip_src.s_addr) { struct socket *tmp; for (tmp = udb.so_next; tmp != &udb; tmp = tmp->so_next) { if ( tmp->so_lport == uh->uh_sport && tmp->so_laddr.s_addr == ip->ip_src.s_addr) { so = tmp; break; } } if (tmp == &udb) so = NULL; else { udpstat.udpps_pcbcachemiss++; udp_last_so = so; } } new_socket: if (so == NULL) { /* * If there's no socket for this packet, * create one */ if ((so = socreate()) == NULL) { Log2(("NAT: IP(id: %hd) failed to create socket\n", ip->ip_id)); goto bad_free_mbuf; } /* * Setup fields */ so->so_laddr = ip->ip_src; so->so_lport = uh->uh_sport; so->so_iptos = ip->ip_tos; if (udp_attach(pData, so) <= 0) { Log2(("NAT: IP(id: %hd) udp_attach errno = %d (%s)\n", ip->ip_id, errno, strerror(errno))); sofree(pData, so); goto bad_free_mbuf; } /* udp_last_so = so; */ /* * XXXXX Here, check if it's in udpexec_list, * and if it is, do the fork_exec() etc. */ } so->so_faddr = ip->ip_dst; /* XXX */ so->so_fport = uh->uh_dport; /* XXX */ Assert(so->so_type == IPPROTO_UDP); /* * DNS proxy */ if ( pData->fUseDnsProxy && CTL_CHECK(ip->ip_dst.s_addr, CTL_DNS) && (uh->uh_dport == RT_H2N_U16_C(53))) { dnsproxy_query(pData, so, m, iphlen); goto done_free_mbuf; } iphlen += sizeof(struct udphdr); m->m_len -= iphlen; m->m_data += iphlen; ttl = ip->ip_ttl = save_ip.ip_ttl; if (ttl != so->so_sottl) { ret = setsockopt(so->s, IPPROTO_IP, IP_TTL, (char *)&ttl, sizeof(ttl)); if (RT_LIKELY(ret == 0)) so->so_sottl = ttl; } tos = save_ip.ip_tos; if (tos != so->so_sotos) { ret = setsockopt(so->s, IPPROTO_IP, IP_TOS, (char *)&tos, sizeof(tos)); if (RT_LIKELY(ret == 0)) so->so_sotos = tos; } { /* * Different OSes have different socket options for DF. We * can't use IP_HDRINCL here as it's only valid for SOCK_RAW. */ # define USE_DF_OPTION(_Optname) \ const int dfopt = _Optname #if defined(IP_MTU_DISCOVER) USE_DF_OPTION(IP_MTU_DISCOVER); #elif defined(IP_DONTFRAG) /* Solaris 11+, FreeBSD */ USE_DF_OPTION(IP_DONTFRAG); #elif defined(IP_DONTFRAGMENT) /* Windows */ USE_DF_OPTION(IP_DONTFRAGMENT); #else USE_DF_OPTION(0); #endif if (dfopt) { int df = (save_ip.ip_off & IP_DF) != 0; #if defined(IP_MTU_DISCOVER) df = df ? IP_PMTUDISC_DO : IP_PMTUDISC_DONT; #endif if (df != so->so_sodf) { ret = setsockopt(so->s, IPPROTO_IP, dfopt, (char *)&df, sizeof(df)); if (RT_LIKELY(ret == 0)) so->so_sodf = df; } } } if ( sosendto(pData, so, m) == -1 && ( !soIgnorableErrorCode(errno) && errno != ENOTCONN)) { m->m_len += iphlen; m->m_data -= iphlen; *ip = save_ip; Log2(("NAT: UDP tx errno = %d (%s) on sent to %RTnaipv4\n", errno, strerror(errno), ip->ip_dst)); icmp_error(pData, m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno)); so->so_m = NULL; LogFlowFuncLeave(); return; } if (so->so_m) m_freem(pData, so->so_m); /* used for ICMP if error on sorecvfrom */ /* restore the orig mbuf packet */ m->m_len += iphlen; m->m_data -= iphlen; *ip = save_ip; so->so_m = m; /* ICMP backup */ LogFlowFuncLeave(); return; bad_free_mbuf: Log2(("NAT: UDP(id: %hd) datagram to %RTnaipv4 with size(%d) claimed as bad\n", ip->ip_id, &ip->ip_dst, ip->ip_len)); done_free_mbuf: /* some services like bootp(built-in), dns(buildt-in) and dhcp don't need sockets * and create new m'buffers to send them to guest, so we'll free their incomming * buffers here. */ if (m != NULL) m_freem(pData, m); LogFlowFuncLeave(); return; } /** * Output a UDP packet. * * @note This function will finally free m! */ int udp_output2(PNATState pData, struct socket *so, struct mbuf *m, struct sockaddr_in *saddr, struct sockaddr_in *daddr, int iptos) { register struct udpiphdr *ui; int error; int mlen = 0; LogFlowFunc(("ENTER: so = %R[natsock], m = %p, saddr = %RTnaipv4, daddr = %RTnaipv4\n", so, m, saddr->sin_addr.s_addr, daddr->sin_addr.s_addr)); /* in case of built-in service so might be NULL */ if (so) Assert(so->so_type == IPPROTO_UDP); /* * Adjust for header */ m->m_data -= sizeof(struct udpiphdr); m->m_len += sizeof(struct udpiphdr); mlen = m_length(m, NULL); /* * Fill in mbuf with extended UDP header * and addresses and length put into network format. */ ui = mtod(m, struct udpiphdr *); memset(ui->ui_x1, 0, 9); ui->ui_pr = IPPROTO_UDP; ui->ui_len = RT_H2N_U16((uint16_t)(mlen - sizeof(struct ip))); /* XXXXX Check for from-one-location sockets, or from-any-location sockets */ ui->ui_src = saddr->sin_addr; ui->ui_dst = daddr->sin_addr; ui->ui_sport = saddr->sin_port; ui->ui_dport = daddr->sin_port; ui->ui_ulen = ui->ui_len; /* * Stuff checksum and output datagram. */ ui->ui_sum = 0; if (udpcksum) { if ((ui->ui_sum = cksum(m, /* sizeof (struct udpiphdr) + */ mlen)) == 0) ui->ui_sum = 0xffff; } ((struct ip *)ui)->ip_len = mlen; ((struct ip *)ui)->ip_ttl = ip_defttl; ((struct ip *)ui)->ip_tos = iptos; udpstat.udps_opackets++; error = ip_output(pData, so, m); return error; } /** * @note This function will free m! */ int udp_output(PNATState pData, struct socket *so, struct mbuf *m, struct sockaddr_in *addr) { struct sockaddr_in saddr, daddr; Assert(so->so_type == IPPROTO_UDP); LogFlowFunc(("ENTER: so = %R[natsock], m = %p, saddr = %RTnaipv4\n", so, m, addr->sin_addr.s_addr)); if (so->so_laddr.s_addr == INADDR_ANY) { if (pData->guest_addr_guess.s_addr != INADDR_ANY) { LogRel2(("NAT: port-forward: using %RTnaipv4 for %R[natsock]\n", pData->guest_addr_guess.s_addr, so)); so->so_laddr = pData->guest_addr_guess; } else { LogRel2(("NAT: port-forward: guest address unknown for %R[natsock]\n", so)); m_freem(pData, m); return 0; } } saddr = *addr; if ((so->so_faddr.s_addr & RT_H2N_U32(pData->netmask)) == pData->special_addr.s_addr) { saddr.sin_addr.s_addr = so->so_faddr.s_addr; if (slirpIsWideCasting(pData, so->so_faddr.s_addr)) { /** * We haven't got real firewall but have got its submodule libalias. */ m->m_flags |= M_SKIP_FIREWALL; /** * udp/137 port is Name Service in NetBIOS protocol. for some reasons Windows guest rejects * accept data from non-aliased server. */ if ( (so->so_fport == so->so_lport) && (so->so_fport == RT_H2N_U16(137))) saddr.sin_addr.s_addr = alias_addr.s_addr; else saddr.sin_addr.s_addr = addr->sin_addr.s_addr; so->so_faddr.s_addr = addr->sin_addr.s_addr; } } /* Any UDP packet to the loopback address must be translated to be from * the forwarding address, i.e. 10.0.2.2. */ if ( (saddr.sin_addr.s_addr & RT_H2N_U32_C(IN_CLASSA_NET)) == RT_H2N_U32_C(INADDR_LOOPBACK & IN_CLASSA_NET)) saddr.sin_addr.s_addr = alias_addr.s_addr; daddr.sin_addr = so->so_laddr; daddr.sin_port = so->so_lport; return udp_output2(pData, so, m, &saddr, &daddr, so->so_iptos); } int udp_attach(PNATState pData, struct socket *so) { struct sockaddr sa_addr; socklen_t socklen = sizeof(struct sockaddr); int status; int opt = 1; AssertReturn(so->so_type == 0, -1); so->so_type = IPPROTO_UDP; so->s = socket(AF_INET, SOCK_DGRAM, 0); if (so->s == -1) goto error; fd_nonblock(so->s); so->so_sottl = 0; so->so_sotos = 0; so->so_sodf = -1; status = sobind(pData, so); if (status != 0) return status; /* success, insert in queue */ so->so_expire = curtime + SO_EXPIRE; /* enable broadcast for later use */ setsockopt(so->s, SOL_SOCKET, SO_BROADCAST, (const char *)&opt, sizeof(opt)); status = getsockname(so->s, &sa_addr, &socklen); if (status == 0) { Assert(sa_addr.sa_family == AF_INET); so->so_hlport = ((struct sockaddr_in *)&sa_addr)->sin_port; so->so_hladdr.s_addr = ((struct sockaddr_in *)&sa_addr)->sin_addr.s_addr; } SOCKET_LOCK_CREATE(so); QSOCKET_LOCK(udb); insque(pData, so, &udb); NSOCK_INC(); QSOCKET_UNLOCK(udb); return so->s; error: Log2(("NAT: can't create datagram socket\n")); return -1; } void udp_detach(PNATState pData, struct socket *so) { if (so != &pData->icmp_socket) { Assert(so->so_type == IPPROTO_UDP); QSOCKET_LOCK(udb); SOCKET_LOCK(so); QSOCKET_UNLOCK(udb); closesocket(so->s); sofree(pData, so); SOCKET_UNLOCK(so); } } struct socket * udp_listen(PNATState pData, u_int32_t bind_addr, u_int port, u_int32_t laddr, u_int lport, int flags) { struct sockaddr_in addr; struct socket *so; socklen_t addrlen = sizeof(struct sockaddr_in); int opt = 1; LogFlowFunc(("ENTER: bind_addr:%RTnaipv4, port:%d, laddr:%RTnaipv4, lport:%d, flags:%x\n", bind_addr, RT_N2H_U16(port), laddr, RT_N2H_U16(lport), flags)); if ((so = socreate()) == NULL) { LogFlowFunc(("LEAVE: NULL\n")); return NULL; } so->s = socket(AF_INET, SOCK_DGRAM, 0); if (so->s == -1) { LogRel(("NAT: can't create datagram socket\n")); RTMemFree(so); LogFlowFunc(("LEAVE: NULL\n")); return NULL; } so->so_expire = curtime + SO_EXPIRE; so->so_type = IPPROTO_UDP; fd_nonblock(so->s); so->so_sottl = 0; so->so_sotos = 0; so->so_sodf = -1; SOCKET_LOCK_CREATE(so); QSOCKET_LOCK(udb); insque(pData, so, &udb); NSOCK_INC(); QSOCKET_UNLOCK(udb); memset(&addr, 0, sizeof(addr)); #ifdef RT_OS_DARWIN addr.sin_len = sizeof(addr); #endif addr.sin_family = AF_INET; addr.sin_addr.s_addr = bind_addr; addr.sin_port = port; if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) { LogRel(("NAT: udp bind to %RTnaipv4:%d failed, error %d\n", addr.sin_addr, RT_N2H_U16(port), errno)); udp_detach(pData, so); LogFlowFunc(("LEAVE: NULL\n")); return NULL; } setsockopt(so->s, SOL_SOCKET, SO_REUSEADDR,(char *)&opt, sizeof(int)); /* setsockopt(so->s, SOL_SOCKET, SO_OOBINLINE,(char *)&opt, sizeof(int)); */ getsockname(so->s,(struct sockaddr *)&addr,&addrlen); so->so_hladdr = addr.sin_addr; so->so_hlport = addr.sin_port; /* XXX: wtf are we setting so_faddr/so_fport here? */ so->so_fport = addr.sin_port; #if 0 /* The original check was completely broken, as the commented out * if statement was always true (INADDR_ANY=0). */ /** @todo vvl - alias_addr should be set (if required) * later by liabalias module. */ if (addr.sin_addr.s_addr == 0 || addr.sin_addr.s_addr == loopback_addr.s_addr) so->so_faddr = alias_addr; else #endif so->so_faddr = addr.sin_addr; so->so_lport = lport; so->so_laddr.s_addr = laddr; if (flags != SS_FACCEPTONCE) so->so_expire = 0; so->so_state = SS_ISFCONNECTED; LogFlowFunc(("LEAVE: %R[natsock]\n", so)); return so; }