ref: c1d40df49550393f3afe53fb6e6d500dfa8eb7a8
dir: /sys/src/9/ip/ipaux.c/
#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" #include "ip.h" #include "ipv6.h" char *v6hdrtypes[Maxhdrtype] = { [HBH] "HopbyHop", [ICMP] "ICMP", [IGMP] "IGMP", [GGP] "GGP", [IPINIP] "IP", [ST] "ST", [TCP] "TCP", [UDP] "UDP", [ISO_TP4] "ISO_TP4", [RH] "Routinghdr", [FH] "Fraghdr", [IDRP] "IDRP", [RSVP] "RSVP", [AH] "Authhdr", [ESP] "ESP", [ICMPv6] "ICMPv6", [NNH] "Nonexthdr", [ISO_IP] "ISO_IP", [IGRP] "IGRP", [OSPF] "OSPF", }; /* * well known IPv6 addresses */ uchar v6Unspecified[IPaddrlen] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; uchar v6loopback[IPaddrlen] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01 }; uchar v6linklocal[IPaddrlen] = { 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; uchar v6linklocalmask[IPaddrlen] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0 }; int v6llpreflen = 8; /* link-local prefix length in bytes */ uchar v6multicast[IPaddrlen] = { 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; uchar v6multicastmask[IPaddrlen] = { 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; int v6mcpreflen = 1; /* multicast prefix length */ uchar v6allnodesN[IPaddrlen] = { 0xff, 0x01, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01 }; uchar v6allroutersN[IPaddrlen] = { 0xff, 0x01, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x02 }; uchar v6allnodesNmask[IPaddrlen] = { 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; int v6aNpreflen = 2; /* all nodes (N) prefix */ uchar v6allnodesL[IPaddrlen] = { 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01 }; uchar v6allroutersL[IPaddrlen] = { 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x02 }; uchar v6allnodesLmask[IPaddrlen] = { 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; int v6aLpreflen = 2; /* all nodes (L) prefix */ uchar v6solicitednode[IPaddrlen] = { 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01, 0xff, 0, 0, 0 }; uchar v6solicitednodemask[IPaddrlen] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x0, 0x0, 0x0 }; int v6snpreflen = 13; ushort ptclcsum(Block *bp, int offset, int len) { uchar *addr; ulong losum, hisum; ushort csum; int odd, blocklen, x; /* Correct to front of data area */ while(bp != nil && offset && offset >= BLEN(bp)) { offset -= BLEN(bp); bp = bp->next; } if(bp == nil) return 0; addr = bp->rp + offset; blocklen = BLEN(bp) - offset; if(bp->next == nil) { if(blocklen < len) len = blocklen; return ptclbsum(addr, len) ^ 0xffff; } losum = 0; hisum = 0; odd = 0; while(len) { x = blocklen; if(len < x) x = len; csum = ptclbsum(addr, x); if(odd) hisum += csum; else losum += csum; odd = (odd+x) & 1; len -= x; bp = bp->next; if(bp == nil) break; blocklen = BLEN(bp); addr = bp->rp; } losum += hisum>>8; losum += (hisum&0xff)<<8; while((csum = losum>>16) != 0) losum = csum + (losum & 0xffff); return losum ^ 0xffff; } enum { Isprefix= 16, }; #define CLASS(p) ((*(uchar*)(p))>>6) void ipv62smcast(uchar *smcast, uchar *a) { ipmove(smcast, v6solicitednode); smcast[13] = a[13]; smcast[14] = a[14]; smcast[15] = a[15]; } /* * parse a hex mac address */ int parsemac(uchar *to, char *from, int len) { char nip[4]; char *p; int i; p = from; memset(to, 0, len); for(i = 0; i < len; i++){ if(p[0] == '\0' || p[1] == '\0') break; nip[0] = p[0]; nip[1] = p[1]; nip[2] = '\0'; p += 2; to[i] = strtoul(nip, 0, 16); if(*p == ':') p++; } return i; } /* * return multicast version if any */ int ipismulticast(uchar *ip) { if(isv4(ip)){ if(isv4mcast(&ip[IPv4off])) return V4; } else if(isv6mcast(ip)) return V6; return 0; } /* * return ip version of a connection */ int convipvers(Conv *c) { if(isv4(c->raddr) && isv4(c->laddr) || ipcmp(c->raddr, IPnoaddr) == 0) return V4; else return V6; } /* * hashing tcp, udp, ... connections */ static ulong iphash(uchar *sa, ushort sp, uchar *da, ushort dp) { return ((sa[IPaddrlen-1]<<24) ^ (sp << 16) ^ (da[IPaddrlen-1]<<8) ^ dp ) % Nipht; } void iphtadd(Ipht *ht, Iphash *h) { ulong hv; if(ipcmp(h->raddr, IPnoaddr) != 0) h->match = IPmatchexact; else { if(ipcmp(h->laddr, IPnoaddr) != 0){ if(h->lport == 0) h->match = IPmatchaddr; else h->match = IPmatchpa; } else { if(h->lport == 0) h->match = IPmatchany; else h->match = IPmatchport; } } lock(ht); hv = iphash(h->raddr, h->rport, h->laddr, h->lport); h->nextiphash = ht->tab[hv]; ht->tab[hv] = h; unlock(ht); } void iphtrem(Ipht *ht, Iphash *h) { ulong hv; Iphash **l; lock(ht); hv = iphash(h->raddr, h->rport, h->laddr, h->lport); for(l = &ht->tab[hv]; (*l) != nil; l = &(*l)->nextiphash) if(*l == h){ (*l) = h->nextiphash; h->nextiphash = nil; break; } unlock(ht); } /* look for a matching iphash with the following precedence * raddr,rport,laddr,lport * laddr,lport * *,lport * laddr,* * *,* */ Iphash* iphtlook(Ipht *ht, uchar *sa, ushort sp, uchar *da, ushort dp) { ulong hv; Iphash *h; lock(ht); /* exact 4 pair match (connection) */ hv = iphash(sa, sp, da, dp); for(h = ht->tab[hv]; h != nil; h = h->nextiphash){ if(h->match != IPmatchexact) continue; if(sp == h->rport && dp == h->lport && ipcmp(sa, h->raddr) == 0 && ipcmp(da, h->laddr) == 0){ unlock(ht); return h; } } /* match local address and port */ hv = iphash(IPnoaddr, 0, da, dp); for(h = ht->tab[hv]; h != nil; h = h->nextiphash){ if(h->match != IPmatchpa) continue; if(dp == h->lport && ipcmp(da, h->laddr) == 0){ unlock(ht); return h; } } /* match just port */ hv = iphash(IPnoaddr, 0, IPnoaddr, dp); for(h = ht->tab[hv]; h != nil; h = h->nextiphash){ if(h->match != IPmatchport) continue; if(dp == h->lport){ unlock(ht); return h; } } /* match local address */ hv = iphash(IPnoaddr, 0, da, 0); for(h = ht->tab[hv]; h != nil; h = h->nextiphash){ if(h->match != IPmatchaddr) continue; if(ipcmp(da, h->laddr) == 0){ unlock(ht); return h; } } /* look for something that matches anything */ hv = iphash(IPnoaddr, 0, IPnoaddr, 0); for(h = ht->tab[hv]; h != nil; h = h->nextiphash){ if(h->match != IPmatchany) continue; unlock(ht); return h; } unlock(ht); return nil; } /* * Move entry to front of Proto.translations * and update the timestamp. * * Proto is locked. */ static Translation* transupdate(Proto *p, Translation *q) { q->time = NOW; /* unlink */ if(q->link != nil && (*q->link = q->next) != nil) q->next->link = q->link; /* link to front */ if((q->next = p->translations) != nil) q->next->link = &q->next; p->translations = q; q->link = &p->translations; return q; } /* * Called with the 4-tuple (sa,sp,da,dp) * that should be source translated, * returning the translation. * * Proto is locked. */ Translation* transforward(Proto *p, Ipht *ht, uchar *sa, int sp, uchar *da, int dp, Route *r) { uchar ia[IPaddrlen]; Routehint rh; Translation *q; Iphash *iph; Ipifc *ifc; int lport; ulong now; int num; /* Translation already exists? */ iph = iphtlook(ht, sa, sp, da, dp); if(iph != nil){ if(iph->trans == 1) return transupdate(p, iphforward(iph)); if(iph->match == IPmatchexact){ netlog(p->f, Logtrans, "trans: backwards collision: %s!%I!%d -> %I!%d\n", p->name, sa, sp, da, dp); return nil; } } /* No route means dont make a new entry */ if(r == nil) return nil; /* Bad forward route? */ if((ifc = r->ifc) == nil){ netlog(p->f, Logtrans, "trans: no interface: %s!%I!%d -> %I!%d\n", p->name, sa, sp, da, dp); return nil; } /* Bad source address? */ if(ipismulticast(sa) || ipforme(p->f, sa) != 0){ netlog(p->f, Logtrans, "trans: bad source address: %s!%I!%d -> %I!%d\n", p->name, sa, sp, da, dp); return nil; } /* Find a source address on the destination interface */ rlock(ifc); memmove(ia, v4prefix, IPv4off); if(!ipv4local(ifc, ia+IPv4off, 0, (r->type & (Rifc|Runi|Rbcast|Rmulti))? da+IPv4off: r->v4.gate)){ runlock(ifc); netlog(p->f, Logtrans, "trans: no source ip: %s!%I!%d -> %I!%d\n", p->name, sa, sp, da, dp); return nil; } runlock(ifc); /* Check backward route */ rh.a = nil; rh.r = nil; if(ipismulticast(da)) r = v4lookup(p->f, sa+IPv4off, ia+IPv4off, nil); else r = v4lookup(p->f, sa+IPv4off, da+IPv4off, &rh); if(r == nil || (r->ifc == ifc && !ifc->reflect)){ netlog(p->f, Logtrans, "trans: bad backward route: %s!%I!%d <- %I <- %I!%d\n", p->name, sa, sp, ia, da, dp); return nil; } /* Find local port */ lport = unusedlport(p); if(lport <= 0){ netlog(p->f, Logtrans, "trans: no local port: %s!%I!%d <- %I <- %I!%d\n", p->name, sa, sp, ia, da, dp); return nil; } /* Reuse expired entries */ num = 0; now = NOW; for(q = p->translations; q != nil; q = q->next) { if(++num >= 1000 || (now - q->time) >= 5*60*1000){ netlog(p->f, Logtrans, "trans: removing %s!%I!%d -> %I!%d -> %I!%d\n", p->name, q->forward.raddr, q->forward.rport, q->backward.laddr, q->backward.lport, q->forward.laddr, q->forward.lport); iphtrem(ht, &q->forward); iphtrem(ht, &q->backward); break; } } if(q == nil){ q = malloc(sizeof(*q)); if(q == nil) return nil; q->link = nil; } /* Match what needs to be forwarded */ q->forward.trans = 1; q->forward.lport = dp; q->forward.rport = sp; ipmove(q->forward.laddr, da); ipmove(q->forward.raddr, sa); /* Match what comes back to us */ q->backward.trans = 2; q->backward.lport = lport; ipmove(q->backward.laddr, ia); if(p->ipproto == 1 || ipismulticast(da)){ q->backward.rport = 0; ipmove(q->backward.raddr, IPnoaddr); } else { q->backward.rport = dp; ipmove(q->backward.raddr, da); } memmove(&q->Routehint, &rh, sizeof(rh)); netlog(p->f, Logtrans, "trans: adding %s!%I!%d -> %I!%d -> %I!%d\n", p->name, q->forward.raddr, q->forward.rport, q->backward.laddr, q->backward.lport, q->forward.laddr, q->forward.lport); iphtadd(ht, &q->forward); iphtadd(ht, &q->backward); return transupdate(p, q); } /* * Check if backward translation is valid and * update timestamp. * * Proto is locked. */ Translation* transbackward(Proto *p, Iphash *iph) { if(iph == nil || iph->trans != 2) return nil; return transupdate(p, iphbackward(iph)); } /* * Checksum adjusting hnputs() */ void hnputs_csum(void *p, ushort v, uchar *pcsum) { ulong csum; ushort o; csum = nhgets(pcsum)^0xFFFF; o = nhgets(p); hnputs(p, v); if(((uchar*)p - pcsum) & 1){ o = o << 8 | o >> 8; v = v << 8 | v >> 8; } csum += o ^ 0xFFFF; csum += v; while(v = csum >> 16) csum = (csum & 0xFFFF) + v; hnputs(pcsum, csum^0xFFFF); }