tsnoopy: add support for DNS packets - plan9port - [fork] Plan 9 from user space
(HTM) git clone git://src.adamsgaard.dk/plan9port
(DIR) Log
(DIR) Files
(DIR) Refs
(DIR) README
(DIR) LICENSE
---
(DIR) commit 7e36b43bba16df64a08c13358ba2a70ae9001770
(DIR) parent 6f61477d2607eb7df816aae3e2e94fb1697554c8
(HTM) Author: Russ Cox <rsc@swtch.com>
Date: Thu, 24 Jul 2008 08:03:42 -0700
snoopy: add support for DNS packets
Diffstat:
A src/cmd/ip/snoopy/dns.c | 429 +++++++++++++++++++++++++++++++
1 file changed, 429 insertions(+), 0 deletions(-)
---
(DIR) diff --git a/src/cmd/ip/snoopy/dns.c b/src/cmd/ip/snoopy/dns.c
t@@ -0,0 +1,429 @@
+#include <u.h>
+#include <libc.h>
+#include <ip.h>
+#include "dat.h"
+#include "protos.h"
+
+enum
+{
+ /* RR types */
+ Ta= 1,
+ Tns= 2,
+ Tmd= 3,
+ Tmf= 4,
+ Tcname= 5,
+ Tsoa= 6,
+ Tmb= 7,
+ Tmg= 8,
+ Tmr= 9,
+ Tnull= 10,
+ Twks= 11,
+ Tptr= 12,
+ Thinfo= 13,
+ Tminfo= 14,
+ Tmx= 15,
+ Ttxt= 16,
+ Trp= 17,
+ Tsig= 24,
+ Tkey= 25,
+ Taaaa= 28,
+ Tcert= 37,
+
+ /* query types (all RR types are also queries) */
+ Tixfr= 251, /* incremental zone transfer */
+ Taxfr= 252, /* zone transfer */
+ Tmailb= 253, /* { Tmb, Tmg, Tmr } */
+ Tall= 255, /* all records */
+
+ /* classes */
+ Csym= 0, /* internal symbols */
+ Cin= 1, /* internet */
+ Ccs, /* CSNET (obsolete) */
+ Cch, /* Chaos net */
+ Chs, /* Hesiod (?) */
+
+ /* class queries (all class types are also queries) */
+ Call= 255, /* all classes */
+
+ /* opcodes */
+ Oquery= 0<<11, /* normal query */
+ Oinverse= 1<<11, /* inverse query */
+ Ostatus= 2<<11, /* status request */
+ Onotify= 4<<11, /* notify slaves of updates */
+ Omask= 0xf<<11, /* mask for opcode */
+
+ /* response codes */
+ Rok= 0,
+ Rformat= 1, /* format error */
+ Rserver= 2, /* server failure (e.g. no answer from something) */
+ Rname= 3, /* bad name */
+ Runimplimented= 4, /* unimplemented */
+ Rrefused= 5, /* we don't like you */
+ Rmask= 0xf, /* mask for response */
+ Rtimeout= 0x10, /* timeout sending (for internal use only) */
+
+ /* bits in flag word (other than opcode and response) */
+ Fresp= 1<<15, /* message is a response */
+ Fauth= 1<<10, /* true if an authoritative response */
+ Ftrunc= 1<<9, /* truncated message */
+ Frecurse= 1<<8, /* request recursion */
+ Fcanrec= 1<<7, /* server can recurse */
+};
+
+typedef struct Hdr Hdr;
+struct Hdr
+{
+ uchar id[2];
+ uchar flags[2];
+ uchar qdcount[2];
+ uchar ancount[2];
+ uchar nscount[2];
+ uchar arcount[2];
+};
+
+
+static char*
+getstr(uchar **pp, int *len, uchar *ep)
+{
+ uchar *p;
+ int n;
+
+ p = *pp;
+ n = *p++;
+ if(p+n > ep)
+ return nil;
+ *len = n;
+ *pp = p+n;
+ return (char*)p;
+}
+
+static char*
+getname(uchar **pp, uchar *bp, uchar *ep)
+{
+ static char buf[2][512];
+ static int toggle;
+ char *tostart, *to;
+ char *toend;
+ int len, off, pointer, n;
+ uchar *p;
+
+ to = buf[toggle^=1];
+ toend = to+sizeof buf[0];
+ tostart = to;
+ p = *pp;
+ len = 0;
+ pointer = 0;
+ while(p < ep && *p){
+ if((*p & 0xc0) == 0xc0){
+ /* pointer to another spot in message */
+ if(pointer == 0)
+ *pp = p + 2;
+ if(pointer++ > 10)
+ return nil;
+ off = ((p[0]<<8) + p[1]) & 0x3ff;
+ p = bp + off;
+ if(p >= ep)
+ return nil;
+ n = 0;
+ continue;
+ }
+ n = *p++;
+ if(to+n >= toend || p+n > ep)
+ return nil;
+ memmove(to, p, n);
+ to += n;
+ p += n;
+ if(*p){
+ if(to >= toend)
+ return nil;
+ *to++ = '.';
+ }
+ }
+ if(to >= toend || p >= ep)
+ return nil;
+ *to = 0;
+ if(!pointer)
+ *pp = ++p;
+ return tostart;
+}
+
+static char*
+tname(int type)
+{
+ static char buf[20];
+
+ switch(type){
+ case Ta:
+ return "a";
+ case Tns:
+ return "ns";
+ case Tmd:
+ return "md";
+ case Tmf:
+ return "mf";
+ case Tcname:
+ return "cname";
+ case Tsoa:
+ return "soa";
+ case Tmb:
+ return "mb";
+ case Tmg:
+ return "mg";
+ case Tmr:
+ return "mr";
+ case Tnull:
+ return "null";
+ case Twks:
+ return "wks";
+ case Tptr:
+ return "ptr";
+ case Thinfo:
+ return "hinfo";
+ case Tminfo:
+ return "minfo";
+ case Tmx:
+ return "mx";
+ case Ttxt:
+ return "txt";
+ case Trp:
+ return "rp";
+ case Tsig:
+ return "sig";
+ case Tkey:
+ return "key";
+ case Taaaa:
+ return "aaaa";
+ case Tcert:
+ return "cert";
+ case Tixfr:
+ return "ixfr";
+ case Taxfr:
+ return "axfr";
+ case Tmailb:
+ return "mailb";
+ case Tall:
+ return "all";
+ }
+ snprint(buf, sizeof buf, "%d", type);
+ return buf;
+}
+
+static char*
+cname(int class)
+{
+ static char buf[40];
+
+ if(class == Cin)
+ return "";
+
+ snprint(buf, sizeof buf, "class=%d", class);
+ return buf;
+}
+
+#define PR(name, len) utfnlen(name, len), name
+
+extern int sflag;
+
+static int
+p_seprint(Msg *m)
+{
+ int i, pref;
+ Hdr *h;
+ uchar *p, *ep;
+ int an, ns, ar, rlen;
+ char *name, *prefix;
+ int len1, len2;
+ char *sym1, *sym2, *sep;
+ int type;
+ static int first = 1;
+
+ if(first){
+ first = 0;
+ quotefmtinstall();
+ }
+
+ if(m->pe - m->ps < sizeof(Hdr))
+ return -1;
+ h = (Hdr*)m->ps;
+ m->pr = nil;
+
+ m->p = seprint(m->p, m->e, "id=%d flags=%04ux %d/%d/%d/%d",
+ NetS(h->id), NetS(h->flags),
+ NetS(h->qdcount), NetS(h->ancount),
+ NetS(h->nscount), NetS(h->arcount));
+ sep = ")\n\t";
+ if(sflag)
+ sep = ") ";
+ p = m->ps + sizeof(Hdr);
+ for(i=0; i<NetS(h->qdcount); i++){
+ name = getname(&p, m->ps, m->pe);
+ if(name == nil || p+4 > m->pe)
+ goto error;
+ m->p = seprint(m->p, m->e, "%sq=(%q %s%s",
+ sep, name, tname(NetS(p)), cname(NetS(p+2)));
+ p += 4;
+ }
+
+ an = NetS(h->ancount);
+ ns = NetS(h->nscount);
+ ar = NetS(h->arcount);
+ while(an+ns+ar > 0){
+ if(an > 0){
+ prefix = "an";
+ an--;
+ }else if(ns > 0){
+ prefix = "ns";
+ ns--;
+ }else{
+ prefix = "ar";
+ ar--;
+ }
+ name = getname(&p, m->ps, m->pe);
+ if(name == nil || p+10 > m->pe)
+ goto error;
+ type = NetS(p);
+ rlen = NetS(p+8);
+ ep = p+10+rlen;
+ if(ep > m->pe)
+ goto error;
+ m->p = seprint(m->p, m->e, "%s%s=(%q %s%s | ttl=%lud",
+ sep, prefix, name, tname(type), cname(NetS(p+2)), NetL(p+4), rlen);
+ p += 10;
+ switch(type){
+ default:
+ p = ep;
+ break;
+ case Thinfo:
+ sym1 = getstr(&p, &len1, ep);
+ if(sym1 == nil)
+ goto error;
+ sym2 = getstr(&p, &len2, ep);
+ if(sym2 == nil)
+ goto error;
+ m->p = seprint(m->p, m->e, " cpu=%.*s os=%.*s",
+ PR(sym1, len1),
+ PR(sym2, len2));
+ break;
+ case Tcname:
+ case Tmb:
+ case Tmd:
+ case Tmf:
+ case Tns:
+ case Tmg:
+ case Tmr:
+ case Tptr:
+ sym1 = getname(&p, m->ps, m->pe);
+ if(sym1 == nil)
+ goto error;
+ m->p = seprint(m->p, m->e, " %q", sym1);
+ break;
+ case Tminfo:
+ sym1 = getname(&p, m->ps, m->pe);
+ if(sym1 == nil)
+ goto error;
+ sym2 = getname(&p, m->ps, m->pe);
+ if(sym2 == nil)
+ goto error;
+ m->p = seprint(m->p, m->e, " %q %q", sym1, sym2);
+ break;
+ case Tmx:
+ if(p+2 >= ep)
+ goto error;
+ pref = NetS(p);
+ p += 2;
+ sym1 = getname(&p, m->ps, m->pe);
+ if(sym1 == nil)
+ goto error;
+ break;
+ case Ta:
+ if(p+4 > ep)
+ goto error;
+ m->p = seprint(m->p, m->e, " %V", p);
+ p += 4;
+ break;
+ case Taaaa:
+ if(p+16 > ep)
+ goto error;
+ m->p = seprint(m->p, m->e, " %I", p);
+ p += 16;
+ break;
+ case Tsoa:
+ sym1 = getname(&p, m->ps, m->pe);
+ if(sym1 == nil)
+ goto error;
+ sym2 = getname(&p, m->ps, m->pe);
+ if(sym2 == nil)
+ goto error;
+ if(p+20 > ep)
+ goto error;
+ m->p = seprint(m->p, m->e, " host=%q rmb=%q serial=%lud refresh=%lud retry=%lud expire=%lud minttl=%lud",
+ sym1, sym2, NetL(p), NetL(p+4),
+ NetL(p+8), NetL(p+12), NetL(p+16));
+ break;
+ case Ttxt:
+ while(p < ep){
+ sym1 = getstr(&p, &len1, ep);
+ if(sym1 == nil)
+ goto error;
+ m->p = seprint(m->p, m->e, " %.*q", PR(sym1, len1));
+ }
+ break;
+ case Tnull:
+ m->p = seprint(m->p, m->e, " %.*H", rlen, p);
+ p += rlen;
+ break;
+ case Trp:
+ sym1 = getname(&p, m->ps, m->pe);
+ if(sym1 == nil)
+ goto error;
+ sym2 = getname(&p, m->ps, m->pe);
+ if(sym2 == nil)
+ goto error;
+ m->p = seprint(m->p, m->e, " rmb=%q rp=%q", sym1, sym2);
+ break;
+ case Tkey:
+ if(rlen < 4)
+ goto error;
+ m->p = seprint(m->p, m->e, " flags=%04ux proto=%d alg=%d %.*H",
+ NetS(p), p[3], p[4], rlen-4, p+4);
+ p += rlen;
+ break;
+
+ case Tsig:
+ if(rlen < 18)
+ goto error;
+ m->p = seprint(m->p, m->e, " type=%d alg=%d labels=%d ttl=%lud exp=%lud incep=%lud tag=%d %.*H",
+ NetS(p), p[3], p[4], NetL(p+4), NetL(p+8), NetL(p+12), NetS(p+16),
+ rlen-18, p+18);
+ p += rlen;
+ break;
+
+ case Tcert:
+ if(rlen < 5)
+ goto error;
+ m->p = seprint(m->p, m->e, " type=%d tag=%d alg=%d %.*H",
+ NetS(p), NetS(p+2), p[4], rlen-5, p+5);
+ p += rlen;
+ break;
+ }
+ if(p != ep)
+ goto error;
+ }
+ return 0;
+
+error:
+ m->p = seprint(m->p, m->e, " packet error!");
+ return 0;
+}
+
+Proto dns =
+{
+ "dns",
+ nil,
+ nil,
+ p_seprint,
+ nil,
+ nil,
+ nil,
+ defaultframer
+};