/* Copyright 1984 by the Massachusetts Institute of Technology */ /* This file contains routines to handle IN packet input checks and * forwarding. This is all done in one place to cut down on stack * frame construction overhead, since this is all the processing that * most packets will need. */ /* *------------------------------------------------------------------ * * $Source: /afs/net.mit.edu/project/cgw/src/gw/in/RCS/infwd.c,v $ * $Revision: 1.7 $ * $Date: 90/09/29 20:09:28 $ * $State: Exp $ * $Author: jon $ * $Locker: $ * * $Log: infwd.c,v $ * Revision 1.7 90/09/29 20:09:28 jon * don't send redirects if ip_send_redirects is not set * * Revision 1.6 89/03/15 08:37:34 jon * add support for PPP proxy interfaces which forward packets addressed to * them down the PPP line instead of responding ourselves * * Revision 1.5 89/03/05 22:57:53 jon * add call to send ttl exceeded icmp messages * * Revision 1.4 88/10/30 20:25:50 jon * Add support for outgoing fragmentation. * * Revision 1.3 87/06/24 14:11:49 jon * Hack better RVD flushing and get rid of cryptic abbreviations in messages. * * * *------------------------------------------------------------------ */ #ifndef lint static char *rcsid_statd_c = "$Header: /afs/net.mit.edu/project/cgw/src/gw/in/RCS/infwd.c,v 1.7 90/09/29 20:09:28 jon Exp $"; #endif lint #include #include #include "../src/const.h" #include "../src/param.h" #include "../src/defs.h" #include "../src/macs.h" #include "../src/net.h" #include "../src/ext.h" #include "in.h" #include "inparam.h" #include "inext.h" #include "inrte.h" #include "inpro.h" #include "rvd.h" /* #include "../ch/ch.h" */ /* Macros; make code smaller and more readable. */ #define infrme() { if (gethq(&inlpq) == NULL) \ addtsk(syshnd, INPPRI, inxmux, 0); \ addq(&inlpq, iob); \ /* if (*inmsgq == NULL) \ signal(inpid, inopc, 0); */ \ return; } #define inlog(rsn) dolog(rsn, mksina(&pkt->i_src), mksina(&pkt->i_dst)); ext char *rvd_packet_names[]; #define log_rvd_flush(rvdtype) dolog (rvdflush, rvd_packet_names[rvdtype-1], mksina (&pkt->i_src), mksina (&pkt->i_dst)); /* Error messages */ static char inqo[] = "IN queue overflow packet from %d.%d.%d.%d to %d.%d.%d.%d on net %d interface %s/%d\n"; static char innvf[] = "IN not V4 packet headr %d on net %d interfac %s/%d\n"; static char inht[] = "IN header trunc %d packet len %d on net %d interfac %s/%d\n"; static char inbc[] = "IN bad header checksum packet from %d.%d.%d.%d to %d.%d.%d.%d net %d interface %s/%d\n"; static char inttlz[] = "IN TTL ran out packet from %d.%d.%d.%d to %d.%d.%d.%d\n"; static char inpt[] = "IN packet truncated %d packet len %d packet from %d.%d.%d.%d to %d.%d.%d.%d\n"; /* now also used in infrg.c */ char indsc[] = "IN packet %d from %d.%d.%d.%d to %d.%d.%d.%d disc, rsn %d\n"; static char rvdflush[] = "IN flushed RVD %s packet from %d.%d.%d.%d to %d.%d.%d.%d.\n"; /* Add buffer to IP packet queue; discard if queue overflows. */ inaddq(iob) reg iorb *iob; { reg net *netp; reg inpkt *pkt; void inxfwd(); if ((numq(&inq) >= bufshr) && (nbfree <= buflow)) { netp = mknet(iob->i_usr2); pkt = mkin(iob->i_addr); niflog(L_INFC) dolog(inqo, mksina(&pkt->i_src), mksina(&pkt->i_dst), mksnet(netp)); inovfin[netp->n_net]++; freebuf(iob); return; } if (gethq(&inq) == NULL) addtsk(syshnd, INPPRI, inxfwd, 0); addq(&inq, iob); } /* IN packet handler; loops over waiting packet list while nothing * more important is happening. The strange name is so that things * get loaded from the library right. */ inxfwd() { while (tstneq(&inq)) infwd(rmq(&inq)); } /* Handle an incoming IN packet. Checksum the header, swab the * length field, check against the iorb length, decrement the * TTL, etc. Forward on, either directly or to a gateway. * Send redirect if next hop gw anet/subnet == src host anet/subnet * and host is w/in mit subnet, etc. */ infwd(iob) iorb *iob; { reg inpkt *pkt; reg net *netp; reg unsw tmp; unsw fofflg; inaddr hst; inia *inina; word code; void inxmux(); iprte *ipr; ext net *inhop(); ext int ip_send_redirects; pkt = mkin(iob->i_addr); if ((pkt->i_ihlver & INHVERM) != INHVER) { niflog(L_ERRU) dolog(innvf, (pkt->i_ihlver & INHVERM), mksnet(mknet(iob->i_usr2)), iob->i_usr6); freebuf(iob); return; } tmp = (pkt->i_ihlver & INHLENM); if (tmp < INMINH) { niflog(L_ERRU) dolog(inht, tmp, iob->i_bxfr, mksnet(mknet(iob->i_usr2))); freebuf(iob); return; } tmp *= INWPHW; if ((cksum(pkt, tmp, 0) + 1) != 0) { niflog(L_ERRU) dolog(inbc, mksina(&pkt->i_src), mksina(&pkt->i_dst), mksnet(mknet(iob->i_usr2))); freebuf(iob); return; } if (--pkt->i_ttl == 0) { niflog(L_ERRU) inlog(inttlz); netp = mknet(iob->i_usr2); icmp_ttl_exceeded((iniatlst[netp->n_net]->inia_addr), pkt, ICMPTTTLE); freebuf(iob); return; } pkt->i_cksum = acksum(INTTLCKA, pkt->i_cksum); if (swab(pkt->i_len) > iob->i_bxfr) { niflog(L_ERRU) dolog(inpt, swab(pkt->i_len), iob->i_bxfr, mksina(&pkt->i_src), mksina(&pkt->i_dst)); freebuf(iob); return; } fofflg = swab(pkt->i_fofflg); if ((fofflg & INUNUF) != 0) { niflog(L_ERRU) dolog(indsc, pkt->i_prot, mksina(&pkt->i_src), mksina(&pkt->i_dst), 0); freebuf(iob); return; } /* RVD punting ... */ if (in_flush_rvd && pkt->i_prot == INRVD) { struct rvdhdr *rvdpkt; byte rvd_packet_type; unsl rvd_packet_type_mask; rvdpkt = ((struct rvdhdr *) (((char * ) pkt) + ((pkt->i_ihlver & INHLENM) * INBPHW))); rvd_packet_type = rvdpkt->rvd_type; rvd_packet_type_mask = 1 << (rvd_packet_type - 1); if (in_flush_rvd == FLUSH_RVD_ALL) { log_rvd_flush (rvd_packet_type); freebuf (iob); return; } switch (rvd_packet_type) { case RVDSPIN: if ((in_flush_rvd & rvd_packet_type_mask) && (in_flush_rvd_spin_mode & rvdpkt->mode)) { log_rvd_flush (rvd_packet_type); freebuf (iob); return; } break; case RVDAUTHSPIN: if ((in_flush_rvd & rvd_packet_type_mask) && (in_flush_rvd_spin_mode & rvdpkt->mode)) { log_rvd_flush (rvd_packet_type); freebuf (iob); return; } break; default: if (in_flush_rvd & rvd_packet_type_mask) { log_rvd_flush (rvd_packet_type); freebuf (iob); return; } } } niflog(L_TRCP) inlog("IN %d.%d.%d.%d -> %d.%d.%d.%d\n"); /* This should be replaced soon with the real internet broadcast * standard. For now, assume that any packet which was broadcast * on the local net is for me. */ if ((pkt->i_dst.i_saddr.i_shst == INLNBRD) || (iob->i_stat & I_BRD)) infrme(); /* Route packet */ if ((netp = inhop(iob, &hst)) == NULL) return; /* See if packet is addressed to me. */ inina = iniatlst[netp->n_net]; while (inina != NULL) { /* It's my packet if the dst is the same as one of my addresses on the outgoing interface. Unless we're fronting for a host on the far end of a point to point link */ if ((pkt->i_dst.i_long == mkina(inina->inia_addr)->i_long) && !(inina->inia_flags & IF_PPP_PROXY)) infrme(); inina = inina->inia_link; } /* Decide whether to send ICMP redirect */ if (ip_send_redirects && netp == mknet(iob->i_usr2) && pkt->i_prot != INICMP && ( ((swab(pkt->i_fofflg)) & INFOFFM) == 0) ) { ipr = ipr_lookup(pkt->i_src.i_long); if (ipr != NULL && ipr->ipr_type == T_DIR && ipr->ipr_netp == netp) inredir((iniatlst[netp->n_net]->inia_addr), &hst, pkt); } if ((code = (*netp->n_send)(iob, netp, P_IN, &hst)) != D_OK) { niflog(L_TRCO) dolog(indsc, pkt->i_prot, mksina(&pkt->i_src), mksina(&pkt->i_dst), code); freebuf(iob); return; } } /* Add buffer to IP packet transmit queue */ inxaddq(iob) iorb *iob; { void inxxmt(); if (gethq(&inxq) == NULL) addtsk(syshnd, INPPRI, inxxmt, 0); addq(&inxq, iob); } /* IN xmt packet handler */ inxxmt() { while(tstneq(&inxq)) { /* if (*gwmsgq != NULL) { addtsk(gwhnd, INPPRI, &inxxmt, 0); return; } This mechanism should be reimplemented */ inxmt(rmq(&inxq)); } } inxmt(iob) iorb *iob; { reg net *netp; inaddr hst; ext net *inhop(); word code; inpkt *pkt; if ((netp = inhop(iob, &hst)) == NULL) return; if ((code = (*netp->n_send)(iob, netp, P_IN, &hst)) != D_OK) { pkt = mkin(iob->i_addr); niflog(L_TRCO) dolog(indsc, pkt->i_prot, mksina(&pkt->i_src), mksina(&pkt->i_dst), code); freebuf(iob); return; } }