From 80f875fd9291b5357941c28cccd6b8aba373c181 Mon Sep 17 00:00:00 2001 From: cinap_lenrek Date: Sun, 7 Jan 2024 23:39:29 +0000 Subject: devip: no more wandering routes Before, it was possible to add routes before the interface existed. The routes would look for their interface lazily as the route was looked up, but this leads to all kinds of hard to explain behaviour when a interface goes away and the routes start wandering to a different interface on their own which they will stick to when a new interface comes up that would match the route better. Instead, we have routes always associated to their desination interface and remove the routes when the interface gets unbound. It is no longer possible to add routes for interfaces that do not exist. This is easier to reason about behaviour as well as allows us to get rid of canrlock(ifc) in findipifc(). All routes inside the routing tree are now by definition up-to-date (as long as we hold the routelock). Callers of v4lookup()/v6lookup() still should check if the ifcid of the interface still matches the route once they have acquired the interface lock. --- sys/src/9/ip/arp.c | 2 +- sys/src/9/ip/ip.c | 2 +- sys/src/9/ip/ip.h | 1 + sys/src/9/ip/ipifc.c | 27 +++--- sys/src/9/ip/iproute.c | 235 ++++++++++++++++++++++--------------------------- sys/src/9/ip/ipv6.c | 2 +- 6 files changed, 124 insertions(+), 145 deletions(-) diff --git a/sys/src/9/ip/arp.c b/sys/src/9/ip/arp.c index 9c51a48a1..a030e75a4 100644 --- a/sys/src/9/ip/arp.c +++ b/sys/src/9/ip/arp.c @@ -672,7 +672,7 @@ drop(Fs *f, Block *bp) else r = v6lookup(f, ((Ip6hdr*)bp->rp)->src, ((Ip6hdr*)bp->rp)->dst, &rh); if(r != nil && (ifc = r->ifc) != nil && canrlock(ifc)){ - if(!waserror()){ + if(ifc->ifcid == r->ifcid && !waserror()){ if((bp->rp[0]&0xF0) == IP_VER4) icmpnohost(f, ifc, bp, &rh); else diff --git a/sys/src/9/ip/ip.c b/sys/src/9/ip/ip.c index a8d2e3836..4d65265e8 100644 --- a/sys/src/9/ip/ip.c +++ b/sys/src/9/ip/ip.c @@ -131,7 +131,7 @@ ipoput4(Fs *f, Block *bp, Ipifc *gating, int ttl, int tos, Routehint *rh) runlock(ifc); nexterror(); } - if(ifc->m == nil) + if(ifc->m == nil || ifc->ifcid != r->ifcid) goto raise; medialen = ifc->maxtu - ifc->m->hsize; diff --git a/sys/src/9/ip/ip.h b/sys/src/9/ip/ip.h index 5a6820f7d..110bc725b 100644 --- a/sys/src/9/ip/ip.h +++ b/sys/src/9/ip/ip.h @@ -630,6 +630,7 @@ extern Route* v4source(Fs *f, uchar *a, uchar *s); extern Route* v6source(Fs *f, uchar *a, uchar *s); extern long routeread(Fs *f, char*, ulong, int); extern long routewrite(Fs *f, Chan*, char*, int); +extern void flushrouteifc(Fs *f, Ipifc *ifc); extern void routetype(int type, char p[8]); /* diff --git a/sys/src/9/ip/ipifc.c b/sys/src/9/ip/ipifc.c index c16e0a660..ce095b52b 100644 --- a/sys/src/9/ip/ipifc.c +++ b/sys/src/9/ip/ipifc.c @@ -183,7 +183,7 @@ ipifcbind(Conv *c, char **argv, int argc) c->inuse++; /* any ancillary structures (like routes) no longer pertain */ - ifc->ifcid++; + flushrouteifc(c->p->f, ifc); /* reopen all the queues closed by a previous unbind */ qreopen(c->rq); @@ -201,6 +201,8 @@ ipifcbind(Conv *c, char **argv, int argc) static char* ipifcunbindmedium(Ipifc *ifc, Medium *m) { + Conv *c = ifc->conv; + if(m == nil || m == &unboundmedium) return Eunbound; @@ -212,12 +214,12 @@ ipifcunbindmedium(Ipifc *ifc, Medium *m) if(m->unbind != nil){ ifc->m = &unboundmedium; /* fake until unbound */ wunlock(ifc); - qunlock(ifc->conv); + qunlock(c); if(!waserror()){ (*m->unbind)(ifc); poperror(); } - qlock(ifc->conv); + qlock(c); wlock(ifc); } @@ -227,17 +229,17 @@ ipifcunbindmedium(Ipifc *ifc, Medium *m) ifc->reassemble = 0; /* close queues to stop queuing of packets */ - qclose(ifc->conv->rq); - qclose(ifc->conv->wq); - qclose(ifc->conv->sq); + qclose(c->rq); + qclose(c->wq); + qclose(c->sq); /* dissociate routes */ - ifc->ifcid++; + flushrouteifc(c->p->f, ifc); ifc->m = nil; ifc->arg = nil; if(m->unbindonclose == 0) - ifc->conv->inuse--; + c->inuse--; return nil; } @@ -1246,8 +1248,7 @@ findipifc(Fs *f, uchar *local, uchar *remote, int type) xspec = 0; for(cp = f->ipifc->conv; *cp != nil; cp++){ ifc = (Ipifc*)(*cp)->ptcl; - if(!canrlock(ifc)) - continue; + rlock(ifc); for(lifc = ifc->lifc; lifc != nil; lifc = lifc->next){ if(type & Runi){ if(ipcmp(remote, lifc->local) == 0) @@ -1258,7 +1259,8 @@ findipifc(Fs *f, uchar *local, uchar *remote, int type) } maskip(remote, lifc->mask, gnet); if(ipcmp(gnet, lifc->net) == 0){ - spec = comprefixlen(remote, lifc->local, IPaddrlen); + spec = comprefixlen(remote, lifc->local, IPaddrlen)<<8; + spec += comprefixlen(local, lifc->local, IPaddrlen); if(spec > xspec){ x = ifc; xifcid = ifc->ifcid; @@ -1268,7 +1270,8 @@ findipifc(Fs *f, uchar *local, uchar *remote, int type) } runlock(ifc); } - if(x != nil && canrlock(x)){ + if(x != nil){ + rlock(x); if(x->ifcid == xifcid) return x; runlock(x); diff --git a/sys/src/9/ip/iproute.c b/sys/src/9/ip/iproute.c index 1efd806e2..57a5ce5de 100644 --- a/sys/src/9/ip/iproute.c +++ b/sys/src/9/ip/iproute.c @@ -170,7 +170,7 @@ matchroute(Route *a, Route *b) return 0; } - if(a->ifc != nil && b->ifc != nil && (a->ifc != b->ifc || a->ifcid != b->ifcid)) + if(a->ifc != b->ifc) return 0; if(*a->tag != 0 && strncmp(a->tag, b->tag, sizeof(a->tag)) != 0) @@ -358,28 +358,42 @@ looknode(Route **cur, Route *r) } static Route* -looknodetag(Route *r, char *tag) +looknodematch(Route *r, int (*match)(Route*, void*), void *arg) { Route *x; if(r == nil) return nil; - - if((x = looknodetag(r->mid, tag)) != nil) + if((x = looknodematch(r->mid, match, arg)) != nil) return x; - if((x = looknodetag(r->left, tag)) != nil) + if((x = looknodematch(r->left, match, arg)) != nil) return x; - if((x = looknodetag(r->right, tag)) != nil) + if((x = looknodematch(r->right, match, arg)) != nil) return x; + if((*match)(r, arg)) + return r; + return nil; +} - if((r->type & Rifc) == 0){ - if(tag == nil || strncmp(tag, r->tag, sizeof(r->tag)) == 0) - return r; - } +static int +matchtag(Route *r, void *arg) +{ + char *tag = (char*)arg; - return nil; + if(r->type & Rifc) + return 0; + return tag == nil || strncmp(tag, r->tag, sizeof(r->tag)) == 0; +} + +static int +matchifc(Route *r, void *arg) +{ + Ipifc *ifc = (Ipifc*)arg; + + return r->ifc == ifc; } + #define V4H(a) ((a&0x07ffffff)>>(32-Lroot-5)) #define V6H(a) (((a)[0]&0x80000000)>>(32-Lroot) | ((a)[(IPllen/2)-1]&(0xffff>>(16-Lroot)))) @@ -470,9 +484,13 @@ mkroute(uchar *a, uchar *mask, uchar *s, uchar *smask, uchar *gate, int type, Ip Route r; int h; + assert(ifc != nil); + memset(&r, 0, sizeof(r)); r.type = type; + r.ifc = ifc; + r.ifcid = ifcid; if(type & Rv4){ x = nhgetl(a+IPv4off); @@ -506,11 +524,6 @@ mkroute(uchar *a, uchar *mask, uchar *s, uchar *smask, uchar *gate, int type, Ip memmove(r.v6.gate, gate, IPaddrlen); } - if(ifc != nil){ - r.ifc = ifc; - r.ifcid = ifcid; - } - if(tag != nil) strncpy(r.tag, tag, sizeof(r.tag)); @@ -535,58 +548,35 @@ delroute(Fs *f, uchar *a, uchar *mask, uchar *s, uchar *smask, uchar *gate, int wunlock(&routelock); } -/* - * get the outgoing interface for route r, - * interface is returned rlock'd. - */ -static Ipifc* -routefindipifc(Route *r, Fs *f) +static void +flushroutematch(Fs *f, int (*match)(Route*, void*), void *arg) { - uchar local[IPaddrlen], gate[IPaddrlen]; - Ipifc *ifc; - int i; - - ifc = r->ifc; - if(ifc != nil && canrlock(ifc)){ - if(ifc->ifcid == r->ifcid) - return ifc; - runlock(ifc); - r->ifc = nil; - } + Route r, *x; + int h; - if(r->type & Rsrc) { - if(r->type & Rv4) { - hnputl(local+IPv4off, r->v4.source); - memmove(local, v4prefix, IPv4off); - } else { - for(i = 0; i < IPllen; i++) - hnputl(local+4*i, r->v6.source[i]); + wlock(&routelock); + for(h = 0; h < nelem(f->v4root); h++) + while((x = looknodematch(f->v4root[h], match, arg)) != nil){ + memmove(&r, x, sizeof(RouteTree) + sizeof(V4route)); + routedel(f, &r); } - } else { - ipmove(local, IPnoaddr); - } - - if(r->type & Rifc) { - if(r->type & Rv4) { - hnputl(gate+IPv4off, r->v4.address); - memmove(gate, v4prefix, IPv4off); - } else { - for(i = 0; i < IPllen; i++) - hnputl(gate+4*i, r->v6.address[i]); + for(h = 0; h < nelem(f->v6root); h++) + while((x = looknodematch(f->v6root[h], match, arg)) != nil){ + memmove(&r, x, sizeof(RouteTree) + sizeof(V6route)); + routedel(f, &r); } - } else { - if(r->type & Rv4) - v4tov6(gate, r->v4.gate); - else - ipmove(gate, r->v6.gate); - } + wunlock(&routelock); +} - ifc = findipifc(f, local, gate, r->type); - if(ifc != nil) { - r->ifc = ifc; - r->ifcid = ifc->ifcid; - } - return ifc; +/* + * flushrouteifc: + * remove all routes associated with ifc (wlock()'ed). + */ +void +flushrouteifc(Fs *f, Ipifc *ifc) +{ + flushroutematch(f, matchifc, ifc); + ifc->ifcid++; /* invalidate all routes */ } /* @@ -639,17 +629,9 @@ v4lookup(Fs *f, uchar *a, uchar *s, Routehint *rh) q = p; p = p->mid; } - if(q != nil){ - ifc = routefindipifc(q, f); - if(ifc == nil) - q = nil; - else { - if(rh != nil){ - rh->r = q; - rh->rgen = v4routegeneration; - } - runlock(ifc); - } + if(rh != nil){ + rh->r = q; + rh->rgen = v4routegeneration; } runlock(&routelock); return q; @@ -736,17 +718,9 @@ v6lookup(Fs *f, uchar *a, uchar *s, Routehint *rh) p = p->mid; next: ; } - if(q != nil){ - ifc = routefindipifc(q, f); - if(ifc == nil) - q = nil; - else { - if(rh != nil){ - rh->r = q; - rh->rgen = v6routegeneration; - } - runlock(ifc); - } + if(rh != nil){ + rh->r = q; + rh->rgen = v6routegeneration; } runlock(&routelock); return q; @@ -770,8 +744,9 @@ v4source(Fs *f, uchar *a, uchar *s) Route *p, *q; Ipifc *ifc; - q = nil; la = nhgetl(a); +again: + q = nil; rlock(&routelock); for(p = f->v4root[V4H(la)]; p != nil;){ if(la < p->v4.address){ @@ -782,11 +757,17 @@ v4source(Fs *f, uchar *a, uchar *s) p = p->right; continue; } - - ifc = routefindipifc(p, f); - if(ifc == nil){ - p = p->mid; - continue; + ifc = p->ifc; + if(!canrlock(ifc)){ + int gen = v4routegeneration; + runlock(&routelock); + rlock(ifc); + rlock(&routelock); + if(v4routegeneration != gen){ + runlock(&routelock); + runlock(ifc); + goto again; + } } splen = 0; if(p->type & Rsrc){ @@ -818,9 +799,10 @@ v6source(Fs *f, uchar *a, uchar *s) Route *p, *q; Ipifc *ifc; - q = nil; for(h = 0; h < IPllen; h++) la[h] = nhgetl(a+4*h); +again: + q = nil; rlock(&routelock); for(p = f->v6root[V6H(la)]; p != nil;){ for(h = 0; h < IPllen; h++){ @@ -845,11 +827,17 @@ v6source(Fs *f, uchar *a, uchar *s) } break; } - - ifc = routefindipifc(p, f); - if(ifc == nil){ - p = p->mid; - continue; + ifc = p->ifc; + if(!canrlock(ifc)){ + int gen = v6routegeneration; + runlock(&routelock); + rlock(ifc); + rlock(&routelock); + if(v6routegeneration != gen){ + runlock(&routelock); + runlock(ifc); + goto again; + } } splen = 0; if(p->type & Rsrc){ @@ -982,16 +970,13 @@ static char* seprintroute(char *p, char *e, Route *r) { uchar addr[IPaddrlen], mask[IPaddrlen], src[IPaddrlen], smask[IPaddrlen], gate[IPaddrlen]; - char type[8], ifbuf[4], *iname; + char type[8], ifbuf[4]; convroute(r, addr, mask, src, smask, gate); routetype(r->type, type); - if(r->ifc != nil && r->ifcid == r->ifc->ifcid) - snprint(iname = ifbuf, sizeof ifbuf, "%d", r->ifc->conv->x); - else - iname = "-"; + snprint(ifbuf, sizeof ifbuf, "%d", r->ifc->conv->x); return seprint(p, e, "%-15I %-4M %-15I %-4s %4.4s %3s %-15I %-4M\n", - addr, mask, gate, type, r->tag, iname, src, smask); + addr, mask, gate, type, r->tag, ifbuf, src, smask); } typedef struct Routewalk Routewalk; @@ -1074,6 +1059,7 @@ routeread(Fs *f, char *p, ulong offset, int n) * 7 add addr mask gate ifc src smask * 8 add addr mask gate type ifc src smask * 9 add addr mask gate type tag ifc src smask + * * 3 del addr mask * 4 del addr mask gate * 5 del addr mask src smask @@ -1088,15 +1074,14 @@ parseroute(Fs *f, char **argv, int argc) uchar addr[IPaddrlen], mask[IPaddrlen]; uchar src[IPaddrlen], smask[IPaddrlen]; uchar gate[IPaddrlen]; + char *ifcstr, *tag; Ipifc *ifc; uchar ifcid; - char *tag; int type; type = 0; tag = nil; - ifc = nil; - ifcid = 0; + ifcstr = nil; ipmove(gate, IPnoaddr); ipmove(src, IPnoaddr); ipmove(smask, IPnoaddr); @@ -1120,13 +1105,9 @@ parseroute(Fs *f, char **argv, int argc) } if(argc == 5 && strcmp(argv[0], "add") == 0) - ifc = findipifcstr(f, argv[4]); - if(argc > 6) - ifc = findipifcstr(f, argv[argc-3]); - if(ifc != nil){ - ifcid = ifc->ifcid; - runlock(ifc); - } + ifcstr = argv[4]; + else if(argc > 6) + ifcstr = argv[argc-3]; if(argc > 7 && (type = parseroutetype(argv[4])) < 0) error(Ebadctl); @@ -1148,6 +1129,15 @@ parseroute(Fs *f, char **argv, int argc) error(Ebadip); } + if(ifcstr != nil) + ifc = findipifcstr(f, ifcstr); + else + ifc = findipifc(f, src, gate, type); + if(ifc == nil) + error("interface not found"); + ifcid = ifc->ifcid; + runlock(ifc); + return mkroute(addr, mask, src, smask, gate, type, ifc, ifcid, tag); } @@ -1156,7 +1146,6 @@ routewrite(Fs *f, Chan *c, char *p, int n) { Cmdbuf *cb; IPaux *a; - Route *x, r; cb = parsecmd(p, n); if(waserror()){ @@ -1166,25 +1155,11 @@ routewrite(Fs *f, Chan *c, char *p, int n) if(cb->nf < 1) error("short control request"); if(strcmp(cb->f[0], "flush") == 0){ - char *tag = cb->nf < 2 ? nil : cb->f[1]; - int h; - - wlock(&routelock); - for(h = 0; h < nelem(f->v4root); h++) - while((x = looknodetag(f->v4root[h], tag)) != nil){ - memmove(&r, x, sizeof(RouteTree) + sizeof(V4route)); - routedel(f, &r); - } - for(h = 0; h < nelem(f->v6root); h++) - while((x = looknodetag(f->v6root[h], tag)) != nil){ - memmove(&r, x, sizeof(RouteTree) + sizeof(V6route)); - routedel(f, &r); - } - wunlock(&routelock); + flushroutematch(f, matchtag, cb->nf < 2 ? nil : cb->f[1]); } else if(strcmp(cb->f[0], "add") == 0 ||strcmp(cb->f[0], "del") == 0 ||strcmp(cb->f[0], "remove") == 0){ - r = parseroute(f, cb->f, cb->nf); + Route r = parseroute(f, cb->f, cb->nf); if(*r.tag == 0){ a = c->aux; strncpy(r.tag, a->tag, sizeof(r.tag)); diff --git a/sys/src/9/ip/ipv6.c b/sys/src/9/ip/ipv6.c index a47b520e6..5d2d43ef1 100644 --- a/sys/src/9/ip/ipv6.c +++ b/sys/src/9/ip/ipv6.c @@ -85,7 +85,7 @@ ipoput6(Fs *f, Block *bp, Ipifc *gating, int ttl, int tos, Routehint *rh) nexterror(); } - if(ifc->m == nil) + if(ifc->m == nil || r->ifcid != ifc->ifcid) goto raise; medialen = ifc->maxtu - ifc->m->hsize; -- cgit v1.2.3