ref: 065c3557af8de1b20d94c2e86a4a29c5d33ccc67
dir: /sys/src/cmd/ip/snoopy/icmp.c/
#include <u.h> #include <libc.h> #include <ip.h> #include "dat.h" #include "protos.h" typedef struct Hdr Hdr; struct Hdr { uchar type; uchar code; uchar cksum[2]; /* Checksum */ uchar data[1]; }; enum { ICMPLEN= 4, }; enum { Ot, /* type */ Op, /* next protocol */ }; static Field p_fields[] = { {"t", Fnum, Ot, "type", } , {0} }; enum { EchoRep= 0, Unreachable= 3, SrcQuench= 4, Redirect= 5, EchoReq= 8, TimeExceed= 11, ParamProb= 12, TSreq= 13, TSrep= 14, InfoReq= 15, InfoRep= 16, }; static Mux p_mux[] = { {"ip", Unreachable, }, {"ip", SrcQuench, }, {"ip", Redirect, }, {"ip", TimeExceed, }, {"ip", ParamProb, }, {0}, }; char *icmpmsg[256] = { [EchoRep] "EchoRep", [Unreachable] "Unreachable", [SrcQuench] "SrcQuench", [Redirect] "Redirect", [EchoReq] "EchoReq", [TimeExceed] "TimeExceed", [ParamProb] "ParamProb", [TSreq] "TSreq", [TSrep] "TSrep", [InfoReq] "InfoReq", [InfoRep] "InfoRep", }; static void p_compile(Filter *f) { if(f->op == '='){ compile_cmp(icmp.name, f, p_fields); return; } if(strcmp(f->s, "ip") == 0){ f->pr = p_mux->pr; f->subop = Op; return; } sysfatal("unknown icmp field or protocol: %s", f->s); } static int p_filter(Filter *f, Msg *m) { Hdr *h; if(m->pe - m->ps < ICMPLEN) return 0; h = (Hdr*)m->ps; m->ps += ICMPLEN; switch(f->subop){ case Ot: if(h->type == f->ulv) return 1; break; case Op: switch(h->type){ case Unreachable: case TimeExceed: case SrcQuench: case Redirect: case ParamProb: m->ps += 4; return 1; } } return 0; } static int p_seprint(Msg *m) { Hdr *h; char *tn; char *p = m->p; char *e = m->e; ushort cksum2, cksum; h = (Hdr*)m->ps; m->ps += ICMPLEN; m->pr = &dump; if(m->pe - m->ps < ICMPLEN) return -1; tn = icmpmsg[h->type]; if(tn == nil) p = seprint(p, e, "t=%ud c=%d ck=%4.4ux", h->type, h->code, (ushort)NetS(h->cksum)); else p = seprint(p, e, "t=%s c=%d ck=%4.4ux", tn, h->code, (ushort)NetS(h->cksum)); if(Cflag){ cksum = NetS(h->cksum); h->cksum[0] = 0; h->cksum[1] = 0; cksum2 = ~ptclbsum((uchar*)h, m->pe - m->ps + ICMPLEN) & 0xffff; if(cksum != cksum2) p = seprint(p,e, " !ck=%4.4ux", cksum2); } switch(h->type){ case EchoRep: case EchoReq: m->ps += 4; p = seprint(p, e, " id=%ux seq=%ux", NetS(h->data), NetS(h->data+2)); break; case TSreq: case TSrep: m->ps += 12; p = seprint(p, e, " orig=%ud rcv=%ux xmt=%ux", NetL(h->data), NetL(h->data+4), NetL(h->data+8)); m->pr = nil; break; case InfoReq: case InfoRep: break; case Unreachable: case TimeExceed: case SrcQuench: m->ps += 4; m->pr = &ip; break; case Redirect: m->ps += 4; m->pr = &ip; p = seprint(p, e, "gw=%V", h->data); break; case ParamProb: m->ps += 4; m->pr = &ip; p = seprint(p, e, "ptr=%2.2ux", h->data[0]); break; } m->p = p; return 0; } Proto icmp = { "icmp", p_compile, p_filter, p_seprint, p_mux, "%lud", p_fields, defaultframer, };