From owner-freebsd-net Tue Jul 9 2:49:42 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 91A9837B400 for ; Tue, 9 Jul 2002 02:49:13 -0700 (PDT) Received: from zelax.ru (rosa.zelax.ru [212.188.91.12]) by mx1.FreeBSD.org (Postfix) with ESMTP id 649EF43E4A for ; Tue, 9 Jul 2002 02:49:03 -0700 (PDT) (envelope-from wr@zelax.ru) Received: (from root@localhost) by zelax.ru (8.9.3/8.9.3) id NAA60324 for freebsd-net@FreeBSD.ORG.KAV; Tue, 9 Jul 2002 13:48:56 +0400 (MSD) (envelope-from wr@zelax.ru) Received: from zelax.ru (slava.local [192.168.11.152]) by zelax.ru (8.9.3/8.9.3) with ESMTP id NAA60312 for ; Tue, 9 Jul 2002 13:48:56 +0400 (MSD) (envelope-from wr@zelax.ru) Message-ID: <3D2B13D0.9000002@zelax.ru> Date: Tue, 09 Jul 2002 12:48:16 -0400 From: "Vyacheslav V. Burdjanadze" Organization: ZELAX User-Agent: Mozilla/5.0 (compatible; MSIE5.5; Windows 98; X-Accept-Language: ru, en MIME-Version: 1.0 To: freebsd-net@FreeBSD.ORG Subject: Forwarding of UDP broadcast Content-Type: multipart/mixed; boundary="------------020207040507030300010903" Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org This is a multi-part message in MIME format. --------------020207040507030300010903 Content-Type: text/plain; charset=KOI8-R; format=flowed Content-Transfer-Encoding: 7bit Hello. I'm developing for RTEMS OS, and thus this post is bit offtopic, but RTEMS uses networking code ported from FreeBSD. I'm trying to implement forwarding of UDP broadcasts to enable MS Network browsing through chain of routers. As I noticed from code - the best place to do it - is udp_input() in udp_usrreq.c. But unfortunately I can't get my code working correct - it seems like I fill IP header incorrectly thus get ``short packet'' either on ip_input or in udp_input on the receiving side :-(. Could someone help me ? (code is attached) --------------020207040507030300010903 Content-Type: text/plain; name="udp_usrreq.c" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="udp_usrreq.c" /* * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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 8.6 (Berkeley) 5/23/95 * $Id: udp_usrreq.c,v 1.11 2002/07/09 09:10:28 cvs Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * UDP protocol implementation. * Per RFC 768, August, 1980. */ #ifndef COMPAT_42 static int udpcksum = 1; #else static int udpcksum = 0; /* XXX */ #endif SYSCTL_INT(_net_inet_udp, UDPCTL_CHECKSUM, checksum, CTLFLAG_RW, &udpcksum, 0, "Calculate UDP checksum"); static u_long udp_sendspace = 9216; /* really max datagram size */ /* 40 1K datagrams */ SYSCTL_INT(_net_inet_udp, UDPCTL_MAXDGRAM, maxdgram, CTLFLAG_RW, &udp_sendspace, 0, "Maximum UDP datagram size"); static u_long udp_recvspace = 40 * (1024 + sizeof(struct sockaddr_in)); SYSCTL_INT(_net_inet_udp, UDPCTL_RECVSPACE, recvspace, CTLFLAG_RW, &udp_recvspace, 0, "Maximum UDP receive buffer size"); static struct inpcbhead udb; /* from udp_var.h */ static struct inpcbinfo udbinfo; #ifndef UDBHASHSIZE #define UDBHASHSIZE 64 #endif /* * UDP statistics */ struct udpstat udpstat; SYSCTL_STRUCT(_net_inet_udp, UDPCTL_STATS, stats, CTLFLAG_RW, &udpstat, udpstat, "UDP statistic"); static struct sockaddr_in udp_in = { sizeof(udp_in), AF_INET }; static void udp_detach __P((struct inpcb *)); static int udp_output __P((struct inpcb *, struct mbuf *, struct mbuf *, struct mbuf *)); static void udp_notify __P((struct inpcb *, int)); /* Added by Vasilkov. This system call is used by snmp agent code. * */ void udp_get_struct_udb (struct inpcbhead * strudb) { memcpy ((char*)strudb, (char*)&udb, sizeof(struct inpcbhead)); } /* * Register sysctl's */ void sysctl_register_udp_usrreq() { sysctl_register(_net_inet_udp,checksum); sysctl_register(_net_inet_udp,maxdgram); sysctl_register(_net_inet_udp,stats); sysctl_register(_net_inet_udp,recvspace); } void udp_init() { LIST_INIT(&udb); udbinfo.listhead = &udb; udbinfo.hashbase = hashinit(UDBHASHSIZE, M_PCB, &udbinfo.hashmask); } #ifdef FORWARD_PROTOCOL static unsigned char udp_ports[65536/8]; /* * Enable/Disable udp port forwarding */ int udp_forward_port(int port,int forward) { int byte = port/8; int offset = port%8; if (forward) udp_ports[byte] |= (0x80 >> offset); else udp_ports[byte] &= ~(0x80 >> offset); return 0; } /* * Check if port should be forwarded */ static int udp_if_forward(int port) { int byte = port/8; int offset = port%8; return (udp_ports[byte] & (0x80 >> offset)); } #endif /* FORWARD_PROTOCOL */ void udp_input(m, iphlen) register struct mbuf *m; int iphlen; { register struct ip *ip; register struct udphdr *uh; register struct inpcb *inp; struct mbuf *opts = 0, *fwd = 0; int len; struct ip save_ip; struct ifnet *ifp = m->m_pkthdr.rcvif; int log_in_vain = 0; int blackhole = 0; /* * Fetch logging flag from interface */ if (ifp->if_ip.ifi_udp & IFNET_UDP_LOG_IN_VAIN) log_in_vain = 1; /* * Check if we should silently discard refused connects */ if (ifp->if_ip.ifi_udp & IFNET_UDP_BLACKHOLE) blackhole = 1; 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 *); if (m->m_len < iphlen + sizeof(struct udphdr)) { if ((m = m_pullup(m, iphlen + sizeof(struct udphdr))) == 0) { udpstat.udps_hdrops++; return; } ip = mtod(m, struct ip *); } uh = (struct udphdr *)((caddr_t)ip + iphlen); #ifdef FORWARD_PROTOCOL /* * Do local copy of mbuf */ if (udp_if_forward(ntohs(uh->uh_dport))) { fwd = m_copypacket(m,M_DONTWAIT); #ifdef FORWARD_DEBUG printf("Copy packet with port %d, iphlen=%d\n",ntohs(uh->uh_dport),ip->ip_len); #endif } #endif /* * Make mbuf data length reflect UDP length. * If not enough data to reflect UDP length, drop. */ len = ntohs((u_short)uh->uh_ulen); if (ip->ip_len != len) { if (len > ip->ip_len || len < sizeof(struct udphdr)) { udpstat.udps_badlen++; goto bad; } 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; /* * Checksum extended UDP header and data. */ if (uh->uh_sum) { ((struct ipovly *)ip)->ih_next = 0; ((struct ipovly *)ip)->ih_prev = 0; ((struct ipovly *)ip)->ih_x1 = 0; ((struct ipovly *)ip)->ih_len = uh->uh_ulen; uh->uh_sum = in_cksum(m, len + sizeof (struct ip)); if (uh->uh_sum) { udpstat.udps_badsum++; m_freem(m); if (fwd) m_freem(fwd); return; } } if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) || in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) { struct inpcb *last; #ifdef FORWARD_PROTOCOL /* * If our router configured to route broadcasts (this may * be required to enable NetBIOS thru router) */ if (fwd) { /* * For each interface that allow directed broadcast * we should reflect this packet with destanation address * equal to interface subnet broadcast address */ struct ifnet *ifp = ifnet; struct mbuf *tmp; struct ip *ip = mtod(fwd,struct ip *); *ip = save_ip; ip->ip_len += iphlen; #ifdef FORWARD_DEBUG printf("Starting broadcast forwarding\n"); #endif while (ifp) { if ((ifp != fwd->m_pkthdr.rcvif) && !(ifp->if_flags & IFF_LOOPBACK) /*&& (ifp->if_ip.ifi_udp & IFNET_UDP_FORWARD_PROTOCOL)*/) { struct ifaddr *ifa = ifp->if_addrlist; #ifdef FORWARD_DEBUG printf("\tForwarding through %s%d\n",ifp->if_name,ifp->if_unit); #endif while(ifa) { int error; struct ip *ip = mtod(fwd, struct ip *); if (ifa->ifa_addr->sa_family == AF_INET) { struct route ro; if (ifp->if_flags | IFF_BROADCAST) { if (ifa->ifa_dstaddr) ip->ip_dst.s_addr = ((struct sockaddr_in *)(ifa->ifa_dstaddr))->sin_addr.s_addr; else { ip->ip_dst.s_addr = ((struct sockaddr_in *)(ifa->ifa_addr))->sin_addr.s_addr; ip->ip_dst.s_addr &= ((struct sockaddr_in *)(ifa->ifa_netmask))->sin_addr.s_addr; ip->ip_dst.s_addr |= ~(((struct sockaddr_in *)(ifa->ifa_netmask))->sin_addr.s_addr); } } else goto bad; #ifdef FORWARD_DEBUG printf("\t\tForwarding to %s\n",inet_ntoa(ip->ip_dst)); #endif bzero(&ro, sizeof ro); tmp = m_copypacket(fwd,M_DONTWAIT); error = ip_output(fwd, NULL, &ro, IP_ALLOWBROADCAST, NULL,0); #ifdef FORWARD_DEBUG if (error) printf("Output error %d\n",error); #endif fwd = tmp; if (!fwd) goto bad; if (ro.ro_rt) RTFREE(ro.ro_rt); } ifa = ifa->ifa_next; } } ifp = ifp->if_next; } m_freem(m); if (fwd) m_freem(fwd); if (opts) m_freem(opts); /* * FIXME: should also pass udp packet to socket */ return ; } #endif /* FORWARD_PROTOCOL */ /* * Deliver a multicast or broadcast datagram to *all* sockets * for which the local and remote addresses and ports match * those of the incoming datagram. This allows more than * one process to receive multi/broadcasts on the same port. * (This really ought to be done for unicast datagrams as * well, but that would cause problems with existing * applications that open both address-specific sockets and * a wildcard socket listening to the same port -- they would * end up receiving duplicates of every unicast datagram. * Those applications open the multiple sockets to overcome an * inadequacy of the UDP socket interface, but for backwards * compatibility we avoid the problem here rather than * fixing the interface. Maybe 4.5BSD will remedy this?) */ /* * Construct sockaddr format source address. */ udp_in.sin_port = uh->uh_sport; udp_in.sin_addr = ip->ip_src; m->m_len -= sizeof (struct udpiphdr); m->m_data += sizeof (struct udpiphdr); /* * Locate pcb(s) for datagram. * (Algorithm copied from raw_intr().) */ last = NULL; for (inp = udb.lh_first; inp != NULL; inp = inp->inp_list.le_next) { if (inp->inp_lport != uh->uh_dport) continue; if (inp->inp_laddr.s_addr != INADDR_ANY) { if (inp->inp_laddr.s_addr != ip->ip_dst.s_addr) continue; } if (inp->inp_faddr.s_addr != INADDR_ANY) { if (inp->inp_faddr.s_addr != ip->ip_src.s_addr || inp->inp_fport != uh->uh_sport) continue; } if (last != NULL) { struct mbuf *n; if ((n = m_copy(m, 0, M_COPYALL)) != NULL) { if (last->inp_flags & INP_CONTROLOPTS || last->inp_socket->so_options & SO_TIMESTAMP) ip_savecontrol(last, &opts, ip, n); if (sbappendaddr(&last->inp_socket->so_rcv, (struct sockaddr *)&udp_in, n, opts) == 0) { m_freem(n); if (opts) m_freem(opts); udpstat.udps_fullsock++; } else sorwakeup(last->inp_socket); opts = 0; } } last = inp; /* * Don't look for additional matches if this one does * not have either the SO_REUSEPORT or SO_REUSEADDR * socket options set. This heuristic avoids searching * through all pcbs in the common case of a non-shared * port. It * assumes that an application will never * clear these options after setting them. */ if (((last->inp_socket->so_options&(SO_REUSEPORT|SO_REUSEADDR)) == 0)) break; } if (last == NULL) { /* * No matching pcb found; discard datagram. * (No need to send an ICMP Port Unreachable * for a broadcast or multicast datgram.) */ udpstat.udps_noport++; udpstat.udps_noportbcast++; goto bad; } if (last->inp_flags & INP_CONTROLOPTS || last->inp_socket->so_options & SO_TIMESTAMP) ip_savecontrol(last, &opts, ip, m); if (sbappendaddr(&last->inp_socket->so_rcv, (struct sockaddr *)&udp_in, m, opts) == 0) { udpstat.udps_fullsock++; goto bad; } sorwakeup(last->inp_socket); if (fwd) m_freem(fwd); return; } /* * Locate pcb for datagram. */ inp = in_pcblookuphash(&udbinfo, ip->ip_src, uh->uh_sport, ip->ip_dst, uh->uh_dport, 1); if (inp == NULL) { if (log_in_vain) { char bufdst[20]; char bufsrc[20]; inet_ntop(AF_INET,&(ip->ip_dst),bufdst,sizeof(bufdst)); inet_ntop(AF_INET,&(ip->ip_src),bufdst,sizeof(bufsrc)); log(LOG_INFO, "Connection attempt to UDP %s:%d" " from %s:%d\n", bufdst, ntohs(uh->uh_dport), bufsrc, ntohs(uh->uh_sport)); } udpstat.udps_noport++; if (m->m_flags & (M_BCAST | M_MCAST)) { udpstat.udps_noportbcast++; goto bad; } *ip = save_ip; /* * If we forced to be silent as much as possible.. */ if (blackhole) goto bad; icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_PORT, 0, 0); if (fwd) m_freem(fwd); return; } /* * Construct sockaddr format source address. * Stuff source address and datagram in user buffer. */ udp_in.sin_port = uh->uh_sport; udp_in.sin_addr = ip->ip_src; if (inp->inp_flags & INP_CONTROLOPTS || inp->inp_socket->so_options & SO_TIMESTAMP) ip_savecontrol(inp, &opts, ip, m); iphlen += sizeof(struct udphdr); m->m_len -= iphlen; m->m_pkthdr.len -= iphlen; m->m_data += iphlen; if (sbappendaddr(&inp->inp_socket->so_rcv, (struct sockaddr *)&udp_in, m, opts) == 0) { udpstat.udps_fullsock++; goto bad; } sorwakeup(inp->inp_socket); if (fwd) m_freem(fwd); return; bad: m_freem(m); if (fwd) m_freem(fwd); if (opts) m_freem(opts); } /* * Notify a udp user of an asynchronous error; * just wake up so that he can collect error status. */ static void udp_notify(inp, errnum) register struct inpcb *inp; int errnum; { inp->inp_socket->so_error = errnum; sorwakeup(inp->inp_socket); sowwakeup(inp->inp_socket); } void udp_ctlinput(cmd, sa, vip) int cmd; struct sockaddr *sa; void *vip; { register struct ip *ip = vip; register struct udphdr *uh; if (!PRC_IS_REDIRECT(cmd) && ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)) return; if (ip) { uh = (struct udphdr *)((caddr_t)ip + (ip->ip_hl << 2)); in_pcbnotify(&udb, sa, uh->uh_dport, ip->ip_src, uh->uh_sport, cmd, udp_notify); } else in_pcbnotify(&udb, sa, 0, zeroin_addr, 0, cmd, udp_notify); } static int udp_output(inp, m, addr, control) register struct inpcb *inp; register struct mbuf *m; struct mbuf *addr, *control; { register struct udpiphdr *ui; register int len = m->m_pkthdr.len; struct in_addr laddr; int s = 0, error = 0; if (control) m_freem(control); /* XXX */ if (len + sizeof(struct udpiphdr) > IP_MAXPACKET) { error = EMSGSIZE; goto release; } if (addr) { laddr = inp->inp_laddr; if (inp->inp_faddr.s_addr != INADDR_ANY) { error = EISCONN; goto release; } /* * Must block input while temporarily connected. */ s = splnet(); error = in_pcbconnect(inp, addr); if (error) { splx(s); goto release; } } else { if (inp->inp_faddr.s_addr == INADDR_ANY) { error = ENOTCONN; goto release; } } /* * Calculate data length and get a mbuf * for UDP and IP headers. */ M_PREPEND(m, sizeof(struct udpiphdr), M_DONTWAIT); if (m == 0) { error = ENOBUFS; if (addr) splx(s); goto release; } /* * Fill in mbuf with extended UDP header * and addresses and length put into network format. */ ui = mtod(m, struct udpiphdr *); ui->ui_next = ui->ui_prev = 0; ui->ui_x1 = 0; ui->ui_pr = IPPROTO_UDP; ui->ui_len = htons((u_short)len + sizeof (struct udphdr)); ui->ui_src = inp->inp_laddr; ui->ui_dst = inp->inp_faddr; ui->ui_sport = inp->inp_lport; ui->ui_dport = inp->inp_fport; ui->ui_ulen = ui->ui_len; /* * Stuff checksum and output datagram. */ ui->ui_sum = 0; if (udpcksum) { /*FIXME: should be taken from ouput interface */ if ((ui->ui_sum = in_cksum(m, sizeof (struct udpiphdr) + len)) == 0) ui->ui_sum = 0xffff; } ((struct ip *)ui)->ip_len = sizeof (struct udpiphdr) + len; ((struct ip *)ui)->ip_ttl = inp->inp_ip_ttl; /* XXX */ ((struct ip *)ui)->ip_tos = inp->inp_ip_tos; /* XXX */ udpstat.udps_opackets++; error = ip_output(m, inp->inp_options, &inp->inp_route, inp->inp_socket->so_options & (SO_DONTROUTE | SO_BROADCAST), inp->inp_moptions,0); if (addr) { in_pcbdisconnect(inp); inp->inp_laddr = laddr; splx(s); } return (error); release: m_freem(m); return (error); } /*ARGSUSED*/ int udp_usrreq(so, req, m, addr, control) struct socket *so; int req; struct mbuf *m, *addr, *control; { struct inpcb *inp = sotoinpcb(so); int error = 0; int s; if (req == PRU_CONTROL) return (in_control(so, (u_long)m, (caddr_t)addr, (struct ifnet *)control)); if (inp == NULL && req != PRU_ATTACH) { error = EINVAL; goto release; } /* * Note: need to block udp_input while changing * the udp pcb queue and/or pcb addresses. */ switch (req) { case PRU_ATTACH: if (inp != NULL) { error = EINVAL; break; } s = splnet(); error = in_pcballoc(so, &udbinfo); splx(s); if (error) break; error = soreserve(so, udp_sendspace, udp_recvspace); if (error) break; ((struct inpcb *) so->so_pcb)->inp_ip_ttl = ip_defttl; /*FIXME: fetch ttl from interface first*/ break; case PRU_DETACH: udp_detach(inp); break; case PRU_BIND: s = splnet(); error = in_pcbbind(inp, addr); splx(s); break; case PRU_LISTEN: error = EOPNOTSUPP; break; case PRU_CONNECT: if (inp->inp_faddr.s_addr != INADDR_ANY) { error = EISCONN; break; } s = splnet(); error = in_pcbconnect(inp, addr); splx(s); if (error == 0) soisconnected(so); break; case PRU_CONNECT2: error = EOPNOTSUPP; break; case PRU_ACCEPT: error = EOPNOTSUPP; break; case PRU_DISCONNECT: if (inp->inp_faddr.s_addr == INADDR_ANY) { error = ENOTCONN; break; } s = splnet(); in_pcbdisconnect(inp); inp->inp_laddr.s_addr = INADDR_ANY; splx(s); so->so_state &= ~SS_ISCONNECTED; /* XXX */ break; case PRU_SHUTDOWN: socantsendmore(so); break; case PRU_SEND: return (udp_output(inp, m, addr, control)); case PRU_ABORT: soisdisconnected(so); udp_detach(inp); break; case PRU_SOCKADDR: in_setsockaddr(inp, addr); break; case PRU_PEERADDR: in_setpeeraddr(inp, addr); break; case PRU_SENSE: /* * stat: don't bother with a blocksize. */ return (0); case PRU_SENDOOB: case PRU_FASTTIMO: case PRU_SLOWTIMO: case PRU_PROTORCV: case PRU_PROTOSEND: error = EOPNOTSUPP; break; case PRU_RCVD: case PRU_RCVOOB: return (EOPNOTSUPP); /* do not free mbuf's */ default: panic("udp_usrreq"); } release: if (control) { printf("udp control data unexpectedly retained\n"); m_freem(control); } if (m) m_freem(m); return (error); } static void udp_detach(inp) struct inpcb *inp; { int s = splnet(); in_pcbdetach(inp); splx(s); } --------------020207040507030300010903-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message