1998/0306/ip/ethermedium.c (diff list | history)

ip/ethermedium.c on 1998/0306
1998/0306		#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" #include "ip.h" #include "kernel.h" typedef struct Etherhdr Etherhdr; struct Etherhdr { uchar d[6]; uchar s[6]; uchar t[2]; }; static void etherread(void *a); static void etherbind(Ipifc *ifc, int argc, char **argv); static void etherunbind(Ipifc *ifc); static void etherbwrite(Ipifc *ifc, Block *bp, int version, uchar *ip); static void etheraddmulti(Ipifc *ifc, uchar *a, uchar *ia); static void etherremmulti(Ipifc *ifc, uchar *a, uchar *ia); static Block* multicastarp(Arpent *a, uchar *mac); static void sendarp(Ipifc *ifc, Arpent *a); static int multicastea(uchar *ea, uchar *ip); static void recvarpproc(Ipifc *ifc); Medium ethermedium = { "ether", 14, 60, 1514, 6, etherbind, etherunbind, etherbwrite, etheraddmulti, etherremmulti, nil, /* pktin */ nil, /* addroute */ nil, /* remroute */ nil, /* flushroute */ nil, /* joinmulti */ nil, /* leavemulti */ }; typedef struct Etherrock Etherrock; struct Etherrock { Proc *arpp; /* arp process */ Proc *readp; /* reading process */ Chan *mchan; /* Data channel */ Chan *achan; /* Arp channel */ Chan *cchan; /* Control channel */ }; /* * ethernet arp request */ enum { ETARP = 0x0806, ETIP = 0x0800, ARPREQUEST = 1, ARPREPLY = 2, }; typedef struct Etherarp Etherarp; struct Etherarp { uchar d[6]; uchar s[6]; uchar type[2]; uchar hrd[2]; uchar pro[2]; uchar hln; uchar pln; uchar op[2]; uchar sha[6]; uchar spa[4]; uchar tha[6]; uchar tpa[4]; }; /* * called to bind an IP ifc to an ethernet device * called with ifc wlock'd */ static void etherbind(Ipifc *ifc, int argc, char **argv) { Chan *mchan, *cchan, *achan; char addr[2*NAMELEN]; char dir[2*NAMELEN]; char *buf; int fd, cfd, n; char *ptr; Etherrock *er; if(argc < 2) error(Ebadarg); mchan = cchan = achan = nil; buf = nil; if(waserror()){ if(mchan != nil) cclose(mchan); if(cchan != nil) cclose(cchan); if(achan != nil) cclose(achan); if(buf != nil) free(buf); nexterror(); } /* * open ip conversation * * the dial will fail if the type is already open on * this device. */ snprint(addr, sizeof(addr), "%s!0x800", argv[2]); fd = kdial(addr, nil, dir, &cfd); if(fd < 0) error("dial 0x800 failed"); mchan = fdtochan(fd, ORDWR, 0, 1); cchan = fdtochan(cfd, ORDWR, 0, 1); kclose(fd); kclose(cfd); /* * get mac address */ snprint(addr, sizeof(addr), "%s/stats", dir); fd = kopen(addr, OREAD); if(fd < 0) error("can't read ether stats"); buf = smalloc(512); n = kread(fd, buf, 511); kclose(fd); if(n <= 0) error(Eio); buf[n] = 0; ptr = strstr(buf, "addr: "); if(!ptr) error(Eio); ptr += 6; parsemac(ifc->mac, ptr, 6); /* * open arp conversation */ snprint(addr, sizeof(addr), "%s!0x806", argv[2]); fd = kdial(addr, nil, nil, nil); if(fd < 0) error("dial 0x806 failed"); achan = fdtochan(fd, ORDWR, 0, 1); kclose(fd); er = smalloc(sizeof(*er)); er->mchan = mchan; er->cchan = cchan; er->achan = achan; ifc->arg = er; free(buf); poperror(); kproc("etherread", etherread, ifc); kproc("recvarpproc", recvarpproc, ifc); } /* * called with ifc wlock'd */ static void etherunbind(Ipifc *ifc) { Etherrock *er = ifc->arg; if(er->readp) postnote(er->readp, 1, "unbind", 0); if(er->arpp) postnote(er->arpp, 1, "unbind", 0); /* wait for readers to die */ while(er->arpp != 0 || er->readp != 0) tsleep(&up->sleep, return0, 0, 300); if(er->mchan != nil) cclose(er->mchan); if(er->achan != nil) cclose(er->achan); if(er->cchan != nil) cclose(er->cchan); free(er); } /* * called by ipoput with a single block to write */ static void etherbwrite(Ipifc *ifc, Block *bp, int version, uchar *ip) { Etherhdr *eh; Arpent *a; uchar mac[6]; Etherrock *er = ifc->arg; if(waserror()) { print("etherbwrite failed\n"); ipifccheckout(ifc); return; } if(ipifccheckin(ifc, ðermedium) < 0){ freeb(bp); poperror(); return; } /* get mac address of destination */ a = arpget(bp, version, ðermedium, ip, mac); if(a){ /* check for broadcast or multicast */ bp = multicastarp(a, mac); if(bp == nil){ sendarp(ifc, a); goto out; } } /* make it a single block with space for the ether header */ bp = padblock(bp, ifc->m->hsize); if(bp->next) bp = concatblock(bp); if(BLEN(bp) < ifc->minmtu) bp = adjustblock(bp, ifc->minmtu); eh = (Etherhdr*)bp->rp; /* copy in mac addresses and ether type */ memmove(eh->s, ifc->mac, sizeof(eh->s)); memmove(eh->d, mac, sizeof(eh->d)); switch(version){ case V4: eh->t[0] = 0x08; eh->t[1] = 0x00; break; case V6: eh->t[0] = 0x86; eh->t[1] = 0xDD; break; } devtab[er->mchan->type]->bwrite(er->mchan, bp, 0); ifc->out++; out: ipifccheckout(ifc); poperror(); } /* * process to read from the ethernet */ static void etherread(void *a) { Ipifc *ifc; Block *bp; Etherrock *er; ifc = a; er = ifc->arg; er->readp = up; /* hide identity under a rock for unbind */ if(waserror()){ er->readp = 0; pexit("hangup", 1); } for(;;){ bp = devtab[er->mchan->type]->bread(er->mchan, ifc->maxmtu, 0); ifc->in++; bp->rp += ifc->m->hsize; if(ifc->lifc == nil) freeb(bp); else ipiput(ifc->lifc->local, bp); } } static void etheraddmulti(Ipifc *ifc, uchar *a, uchar *) { uchar mac[6]; char buf[64]; Etherrock *er = ifc->arg; multicastea(mac, a); sprint(buf, "addmulti %E", mac); devtab[er->cchan->type]->write(er->cchan, buf, strlen(buf), 0); } static void etherremmulti(Ipifc *ifc, uchar *a, uchar *) { uchar mac[6]; char buf[64]; Etherrock *er = ifc->arg; multicastea(mac, a); sprint(buf, "remmulti %E", mac); devtab[er->cchan->type]->write(er->cchan, buf, strlen(buf), 0); } /* * send an ethernet arp * (only v4, v6 uses the neighbor discovery, rfc1970) */ static void sendarp(Ipifc *ifc, Arpent *a) { int n; Block *bp; Etherarp *e; Etherrock *er = ifc->arg; /* don't do anything if it's been less than a second since the last */ if(msec - a->time < 1000){ arprelease(a); return; } /* remove all but the last message */ while((bp = a->hold) != nil){ if(bp == a->last) break; a->hold = bp->list; freeblist(bp); } /* try to keep it around for a second more */ a->time = msec; arprelease(a); n = sizeof(Etherarp); if(n < a->type->minmtu) n = a->type->minmtu; bp = allocb(n); memset(bp->rp, 0, n); e = (Etherarp*)bp->rp; memmove(e->tpa, a->ip+IPv4off, sizeof(e->tpa)); ipv4local(ifc, e->spa); memmove(e->sha, ifc->mac, sizeof(e->sha)); memset(e->d, 0xff, sizeof(e->d)); /* ethernet broadcast */ memmove(e->s, ifc->mac, sizeof(e->s)); hnputs(e->type, ETARP); hnputs(e->hrd, 1); hnputs(e->pro, ETIP); e->hln = sizeof(e->sha); e->pln = sizeof(e->spa); hnputs(e->op, ARPREQUEST); bp->wp += n; n = devtab[er->achan->type]->bwrite(er->achan, bp, 0); if(n < 0) print("arp: send: %r\n"); } static void recvarp(Ipifc *ifc) { int n; Block *ebp, *rbp; Etherarp *e, *r; uchar ip[IPaddrlen]; Etherrock *er = ifc->arg; ebp = devtab[er->achan->type]->bread(er->achan, ifc->maxmtu, 0); if(ebp == nil) { print("arp: rcv: %r\n"); return; } e = (Etherarp*)ebp->rp; switch(nhgets(e->op)) { default: break; case ARPREPLY: arpenter(ifc, V4, e->spa, e->sha, ðermedium, 0); break; case ARPREQUEST: /* don't answer arps till we know who we are */ if(ifc->lifc == 0) break; /* check for someone that think's they're me */ v4tov6(ip, e->spa); if(iplocalonifc(ifc, ip)){ if(memcmp(e->sha, ifc->mac, sizeof(e->sha)) != 0) print("arp: 0x%E also has ip addr %V\n", e->sha, e->spa); } else { if(memcmp(e->sha, ifc->mac, sizeof(e->sha)) == 0){ print("arp: %V also has ether addr %E\n", e->spa, e->sha); break; } } /* refresh what we know about sender */ arpenter(ifc, V4, e->spa, e->sha, ðermedium, 1); /* answer only requests for our address or systems we're proxying for */ v4tov6(ip, e->tpa); if(!iplocalonifc(ifc, ip)) if(ipproxyifc(ifc, ip) == 0) break; /* print("arp: rem %I %E (for %I)\n", e->spa, e->sha, e->tpa); /**/ n = sizeof(Etherarp); if(n < ifc->minmtu) n = ifc->minmtu; rbp = allocb(n); r = (Etherarp*)rbp->rp; memset(r, 0, sizeof(Etherarp)); hnputs(r->type, ETARP); hnputs(r->hrd, 1); hnputs(r->pro, ETIP); r->hln = sizeof(r->sha); r->pln = sizeof(r->spa); hnputs(r->op, ARPREPLY); memmove(r->tha, e->sha, sizeof(r->tha)); memmove(r->tpa, e->spa, sizeof(r->tpa)); memmove(r->sha, ifc->mac, sizeof(r->sha)); memmove(r->spa, e->tpa, sizeof(r->spa)); memmove(r->d, e->sha, sizeof(r->d)); memmove(r->s, ifc->mac, sizeof(r->s)); rbp->wp += n; n = devtab[er->achan->type]->bwrite(er->achan, rbp, 0); if(n < 0) print("arp: write: %r\n"); } freeb(ebp); } static void recvarpproc(Ipifc *ifc) { Etherrock *er = ifc->arg; er->arpp = up; if(waserror()){ er->arpp = 0; pexit("hangup", 1); } for(;;) recvarp(ifc); } static int multicastea(uchar *ea, uchar *ip) { int x; switch(x = ipismulticast(ip)){ case V4: ea[0] = 0x01; ea[1] = 0x00; ea[2] = 0x5e; ea[3] = ip[13] & 0x7f; ea[4] = ip[14]; ea[5] = ip[15]; break; case V6: ea[0] = 0x33; ea[1] = 0x33; ea[2] = ip[12]; ea[3] = ip[13]; ea[4] = ip[14]; ea[5] = ip[15]; break; } return x; } /* * fill in an arp entry for broadcast or multicast * addresses */ static Block* multicastarp(Arpent *a, uchar *mac) { /* is it broadcast? */ switch(ipforme(a->ip)){ case Runi: return nil; case Rbcast: memset(mac, 0xff, 6); return arpresolve(a, ðermedium, mac); default: break; } /* if multicast, fill in mac */ switch(multicastea(mac, a->ip)){ case V4: case V6: return arpresolve(a, ðermedium, mac); } /* let arp take care of it */ return nil; }