ref: 53fbb0515159465421053c3165b1aa9da196aa4d
dir: /sys/src/cmd/ip/dhcp6d.c/
/* minimal stateless DHCPv6 server for network boot */ #include <u.h> #include <libc.h> #include <ip.h> #include <bio.h> #include <ndb.h> enum { Eaddrlen = 6, SOLICIT = 1, ADVERTISE, REQUEST, CONFIRM, RENEW, REBIND, REPLY, RELEASE, DECLINE, RECONFIGURE, INFOREQ, RELAYFORW, RELAYREPL, }; typedef struct Req Req; struct Req { int tra; Udphdr *udp; Ipifc *ifc; int ncid; uchar cid[256]; uchar ips[IPaddrlen*8]; int nips; Ndb *db; Ndbtuple *t; struct { int t; uchar *p; uchar *e; } req; struct { int t; uchar *p; uchar *e; } resp; }; typedef struct Otab Otab; struct Otab { int t; int (*f)(uchar *, int, Otab*, Req*); char *q[3]; int done; }; static Otab otab[]; static Ipifc *ipifcs; static ulong starttime; static char *ndbfile; static char *netmtpt = "/net"; static int debug; static uchar v6loopback[IPaddrlen] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }; /* * open ndbfile as db if not already open. also check for stale data * and reload as needed. */ static Ndb * opendb(void) { static ulong lastcheck; static Ndb *db; ulong now = time(nil); /* check no more often than once every minute */ if(db == nil) { db = ndbopen(ndbfile); if(db != nil) lastcheck = now; } else if(now >= lastcheck + 60) { if (ndbchanged(db)) ndbreopen(db); lastcheck = now; } return db; } static Ipifc* findifc(char *net, uchar ip[IPaddrlen]) { Ipifc *ifc; Iplifc *lifc; ipifcs = readipifc(net, ipifcs, -1); for(ifc = ipifcs; ifc != nil; ifc = ifc->next) for(lifc = ifc->lifc; lifc != nil; lifc = lifc->next) if(ipcmp(lifc->ip, ip) == 0) return ifc; return nil; } static Iplifc* localonifc(Ipifc *ifc, uchar ip[IPaddrlen]) { Iplifc *lifc; uchar net[IPaddrlen]; for(lifc = ifc->lifc; lifc != nil; lifc = lifc->next){ maskip(ip, lifc->mask, net); if(ipcmp(net, lifc->net) == 0) return lifc; } return nil; } static int openlisten(char *net) { int fd, cfd; char data[128], devdir[40]; Ipifc *ifc; Iplifc *lifc; sprint(data, "%s/udp!*!dhcp6s", net); cfd = announce(data, devdir); if(cfd < 0) sysfatal("can't announce: %r"); if(fprint(cfd, "headers") < 0) sysfatal("can't set header mode: %r"); ipifcs = readipifc(net, ipifcs, -1); for(ifc = ipifcs; ifc != nil; ifc = ifc->next){ if(strcmp(ifc->dev, "/dev/null") == 0) continue; for(lifc = ifc->lifc; lifc != nil; lifc = lifc->next){ if(!ISIPV6LINKLOCAL(lifc->ip)) continue; if(fprint(cfd, "addmulti %I ff02::1:2", lifc->ip) < 0) fprint(2, "addmulti: %I: %r\n", lifc->ip); } } sprint(data, "%s/data", devdir); fd = open(data, ORDWR); if(fd < 0) sysfatal("open udp data: %r"); return fd; } static uchar* gettlv(int x, int *plen, uchar *p, uchar *e) { int t; int l; if(plen != nil) *plen = 0; while(p+4 <= e){ t = p[0]<<8 | p[1]; l = p[2]<<8 | p[3]; if(p+4+l > e) break; if(t == x){ if(plen != nil) *plen = l; return p+4; } p += l+4; } return nil; } static int getv6ips(uchar *ip, int n, Ndbtuple *t, char *attr) { int r = 0; if(n < IPaddrlen) return 0; if(*attr == '@') attr++; for(; t != nil; t = t->entry){ if(strcmp(t->attr, attr) != 0) continue; if(parseip(ip, t->val) == -1) continue; if(isv4(ip)) continue; ip += IPaddrlen; r += IPaddrlen; if(r >= n) break; } return r; } static int lookupips(uchar *ip, int n, Ndb *db, uchar mac[Eaddrlen]) { Ndbtuple *t; Ndbs s; char val[256], *attr; int r; /* * use hardware address to find an ip address */ attr = "ether"; snprint(val, sizeof val, "%E", mac); t = ndbsearch(db, &s, attr, val); r = 0; while(t != nil){ r += getv6ips(ip + r, n - r, t, "ip"); ndbfree(t); if(r >= n) break; t = ndbsnext(&s, attr, val); } return r; } static uchar* clientea(Req *r) { static uchar ea[Eaddrlen]; u32int type; uchar *ip; if(r->ncid >= 4+Eaddrlen){ type = r->cid[0]<<24 | r->cid[1]<<16 | r->cid[2]<<8 | r->cid[3]; switch(type){ case 0x00010001: case 0x00030001: return r->cid + r->ncid - Eaddrlen; } } ip = r->udp->raddr; ea[0] = ip[8] ^ 2; ea[1] = ip[9]; ea[2] = ip[10]; ea[3] = ip[13]; ea[4] = ip[14]; ea[5] = ip[15]; return ea; } static void clearotab(void) { Otab *o; for(o = otab; o->t != 0; o++) o->done = 0; } static Otab* findotab(int t) { Otab *o; for(o = otab; o->t != 0; o++) if(o->t == t) return o; return nil; } static int addoption(Req *r, int t) { Otab *o; int n; if(r->resp.p+4 > r->resp.e) return -1; o = findotab(t); if(o == nil || o->f == nil || o->done) return -1; o->done = 1; n = (*o->f)(r->resp.p+4, r->resp.e - (r->resp.p+4), o, r); if(n < 0 || r->resp.p+4+n > r->resp.e) return -1; r->resp.p[0] = t>>8, r->resp.p[1] = t; r->resp.p[2] = n>>8, r->resp.p[3] = n; if(debug) fprint(2, "%d(%.*H)\n", t, n, r->resp.p+4); r->resp.p += 4+n; return n; } static void usage(void) { fprint(2, "%s [-d] [-f ndbfile] [-x netmtpt]\n", argv0); exits("usage"); } void main(int argc, char *argv[]) { uchar ibuf[4096], obuf[4096]; Req r[1]; int fd, n, i; fmtinstall('H', encodefmt); fmtinstall('I', eipfmt); fmtinstall('E', eipfmt); ARGBEGIN { case 'd': debug++; break; case 'f': ndbfile = EARGF(usage()); break; case 'x': netmtpt = EARGF(usage()); break; default: usage(); } ARGEND; starttime = time(nil) - 946681200UL; if(opendb() == nil) sysfatal("opendb: %r"); fd = openlisten(netmtpt); /* put process in background */ if(!debug) switch(rfork(RFNOTEG|RFPROC|RFFDG)) { default: exits(nil); case -1: sysfatal("fork: %r"); case 0: break; } while((n = read(fd, ibuf, sizeof(ibuf))) > 0){ if(n < Udphdrsize+4) continue; r->udp = (Udphdr*)ibuf; if(isv4(r->udp->raddr)) continue; if((r->ifc = findifc(netmtpt, r->udp->ifcaddr)) == nil) continue; if(localonifc(r->ifc, r->udp->raddr) == nil) continue; memmove(obuf, ibuf, Udphdrsize); r->req.p = ibuf+Udphdrsize; r->req.e = ibuf+n; r->resp.p = obuf+Udphdrsize; r->resp.e = &obuf[sizeof(obuf)]; r->tra = r->req.p[1]<<16 | r->req.p[2]<<8 | r->req.p[3]; r->req.t = r->req.p[0]; if(debug) fprint(2, "%I->%I(%s) typ=%d tra=%x\n", r->udp->raddr, r->udp->laddr, r->ifc->dev, r->req.t, r->tra); switch(r->req.t){ default: continue; case SOLICIT: r->resp.t = ADVERTISE; break; case REQUEST: case INFOREQ: r->resp.t = REPLY; break; } r->resp.p[0] = r->resp.t; r->resp.p[1] = r->tra>>16; r->resp.p[2] = r->tra>>8; r->resp.p[3] = r->tra; r->req.p += 4; r->resp.p += 4; r->t = nil; clearotab(); /* Server Identifier */ if(addoption(r, 2) < 0) continue; /* Client Identifier */ if(addoption(r, 1) < 0) continue; if((r->db = opendb()) == nil) continue; r->nips = lookupips(r->ips, sizeof(r->ips), r->db, clientea(r))/IPaddrlen; if(debug){ for(i=0; i<r->nips; i++) fprint(2, "ip=%I\n", r->ips+i*IPaddrlen); } addoption(r, 3); addoption(r, 6); write(fd, obuf, r->resp.p-obuf); if(debug) fprint(2, "\n"); } exits(nil); } static int oclientid(uchar *w, int n, Otab*, Req *r) { int len; uchar *p; if((p = gettlv(1, &len, r->req.p, r->req.e)) == nil) return -1; if(len > sizeof(r->cid) || n < len) return -1; memmove(w, p, len); memmove(r->cid, p, len); r->ncid = len; return len; } static int oserverid(uchar *w, int n, Otab*, Req *r) { int len; uchar *p; if(n < 4+4+Eaddrlen) return -1; w[0] = 0, w[1] = 1; /* duid type: link layer address + time*/ w[2] = 0, w[3] = 1; /* hw type: ethernet */ w[4] = starttime>>24; w[5] = starttime>>16; w[6] = starttime>>8; w[7] = starttime; myetheraddr(w+8, r->ifc->dev); /* check if server id matches from the request */ p = gettlv(2, &len, r->req.p, r->req.e); if(p != nil && (len != 4+4+Eaddrlen || memcmp(w, p, 4+4+Eaddrlen) != 0)) return -1; return 4+4+Eaddrlen; } static int oiana(uchar *w, int n, Otab*, Req *r) { int i, len; uchar *p; p = gettlv(3, &len, r->req.p, r->req.e); if(p == nil || len < 3*4) return -1; len = 3*4 + (4+IPaddrlen+2*4)*r->nips; if(n < len) return -1; memmove(w, p, 3*4); w += 3*4; for(i = 0; i < r->nips; i++){ w[0] = 0, w[1] = 5; w[2] = 0, w[3] = IPaddrlen+2*4; w += 4; memmove(w, r->ips + i*IPaddrlen, IPaddrlen); w += IPaddrlen; memset(w, 255, 2*4); w += 2*4; } return len; } static Ndbtuple* lookup(Req *r, char *av[], int ac) { Ndbtuple *t; char *s; if(ac <= 0) return nil; t = nil; if(r->nips > 0){ int i; /* use the target ip's to lookup info if any */ for(i=0; i<r->nips; i++){ s = smprint("%I", &r->ips[i*IPaddrlen]); t = ndbconcatenate(t, ndbipinfo(r->db, "ip", s, av, ac)); free(s); } } else { Iplifc *lifc; /* use the ipv6 networks on the interface */ for(lifc=r->ifc->lifc; lifc!=nil; lifc=lifc->next){ if(isv4(lifc->ip) || ipcmp(lifc->ip, v6loopback) == 0 || ISIPV6LINKLOCAL(lifc->ip)) continue; s = smprint("%I", lifc->net); t = ndbconcatenate(t, ndbipinfo(r->db, "ip", s, av, ac)); free(s); } } return t; } static int oro(uchar*, int, Otab *o, Req *r) { uchar *p; char *av[100]; int i, j, l, ac; Ndbtuple *t; p = gettlv(6, &l, r->req.p, r->req.e); if(p == nil || l < 2) return -1; ac = 0; for(i=0; i<l; i+=2){ if((o = findotab(p[i]>>8 | p[i+1])) == nil || o->done) continue; for(j=0; j<3 && o->q[j]!=nil && ac<nelem(av); j++) av[ac++] = o->q[j]; } r->t = lookup(r, av, ac); if(debug){ fprint(2, "ndb("); for(t = r->t; t != nil; t = t->entry){ fprint(2, "%s=%s ", t->attr, t->val); if(t->entry != nil && t->entry != t->line) fprint(2, "\n"); } fprint(2, ")\n"); } /* process the options */ for(i=0; i<l; i+=2) addoption(r, p[i]>>8 | p[i+1]); ndbfree(r->t); r->t = nil; return -1; } static int oservers(uchar *w, int n, Otab *o, Req *r) { return getv6ips(w, n, r->t, o->q[0]); } static int odomainlist(uchar *w, int n, Otab *o, Req *q) { char val[256]; Ndbtuple *t; int l, r; char *s; r = 0; for(t = q->t; t != nil; t = t->entry){ if(strcmp(t->attr, o->q[0]) != 0) continue; if(utf2idn(t->val, val, sizeof(val)) <= 0) continue; for(s = val; *s != 0; s++){ for(l = 0; *s != 0 && *s != '.'; l++) s++; if(r+1+l > n) return -1; w[r++] = l; memmove(w+r, s-l, l); r += l; if(*s != '.') break; } if(r >= n) return -1; w[r++] = 0; } return r; } static int obootfileurl(uchar *w, int n, Otab *, Req *q) { uchar ip[IPaddrlen]; Ndbtuple *bootf; if((bootf = ndbfindattr(q->t, q->t, "bootf")) == nil) return -1; if(strstr(bootf->val, "://") != nil) return snprint((char*)w, n, "%s", bootf->val); else if(getv6ips(ip, sizeof(ip), q->t, "tftp")) return snprint((char*)w, n, "tftp://[%I]/%s", ip, bootf->val); return -1; } static Otab otab[] = { { 1, oclientid, }, { 2, oserverid, }, { 3, oiana, }, { 6, oro, }, { 23, oservers, "@dns" }, { 24, odomainlist, "dnsdomain" }, { 59, obootfileurl, "bootf", "@tftp", }, { 0 }, };