ref: 15d1425b276495a82621a8d075176a59a512cdf3
dir: /sys/src/cmd/ip/snoopy/igmp.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 timeout; uchar cksum[2]; /* Checksum */ uchar group[4]; }; enum { IGMPLEN= 8, }; enum { Ot, /* type */ Oto, /* timeout */ Ock, /* cksum */ Og, /* group */ }; static Field p_fields[] = { {"t", Fnum, Ot, "type", }, {"to", Fnum, Oto, "timeout", }, {"ck", Fnum, Ock, "cksum", }, {"g", Fv4ip, Og, "group", }, {0} }; enum { Query = 0x11, Report = 0x12, ReportV2 = 0x16, Leave = 0x17, }; static Mux p_mux[] = { {0}, }; char *igmpmsg[256] = { [Query] "Query", [Report] "Report", [ReportV2] "ReportV2", [Leave] "Leave", }; static void p_compile(Filter *f) { if(f->op == '='){ compile_cmp(igmp.name, f, p_fields); return; } sysfatal("unknown igmp field or protocol: %s", f->s); } static int p_filter(Filter *f, Msg *m) { Hdr *h; if(m->pe - m->ps < IGMPLEN) return 0; h = (Hdr*)m->ps; m->ps += IGMPLEN; switch(f->subop){ case Ot: if(h->type == f->ulv) return 1; break; } 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; if(m->pe - m->ps < IGMPLEN) return -1; m->ps += IGMPLEN; m->pr = &dump; tn = igmpmsg[h->type]; if(tn == nil) p = seprint(p, e, "t=%ud to=%d ck=%4.4ux g=%V", h->type, h->timeout, (ushort)NetS(h->cksum), h->group); else p = seprint(p, e, "t=%s to=%d ck=%4.4ux g=%V", tn, h->timeout, (ushort)NetS(h->cksum), h->group); if(Cflag){ cksum = NetS(h->cksum); h->cksum[0] = 0; h->cksum[1] = 0; cksum2 = ~ptclbsum((uchar*)h, m->pe - m->ps + IGMPLEN) & 0xffff; if(cksum != cksum2) p = seprint(p,e, " !ck=%4.4ux", cksum2); } m->p = p; return 0; } Proto igmp = { "igmp", p_compile, p_filter, p_seprint, p_mux, "%lud", p_fields, defaultframer, };