From 0d0f7a0e7c32842edff533246a1f8523306f9ab0 Mon Sep 17 00:00:00 2001 From: John Denker Date: Fri, 1 Jun 2012 23:07:51 -0700 Subject: as downloaded : ucspi-tcp --- ucspi-tcp-0.88/dns_packet.c | 77 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 ucspi-tcp-0.88/dns_packet.c (limited to 'ucspi-tcp-0.88/dns_packet.c') diff --git a/ucspi-tcp-0.88/dns_packet.c b/ucspi-tcp-0.88/dns_packet.c new file mode 100644 index 0000000..04a2cc8 --- /dev/null +++ b/ucspi-tcp-0.88/dns_packet.c @@ -0,0 +1,77 @@ +/* +DNS should have used LZ77 instead of its own sophomoric compression algorithm. +*/ + +#include "error.h" +#include "dns.h" + +unsigned int dns_packet_copy(char *buf,unsigned int len,unsigned int pos,char *out,unsigned int outlen) +{ + while (outlen) { + if (pos >= len) { errno = error_proto; return 0; } + *out = buf[pos++]; + ++out; --outlen; + } + return pos; +} + +unsigned int dns_packet_skipname(char *buf,unsigned int len,unsigned int pos) +{ + unsigned char ch; + + for (;;) { + if (pos >= len) break; + ch = buf[pos++]; + if (ch >= 192) return pos + 1; + if (ch >= 64) break; + if (!ch) return pos; + pos += ch; + } + + errno = error_proto; + return 0; +} + +unsigned int dns_packet_getname(char *buf,unsigned int len,unsigned int pos,char **d) +{ + unsigned int loop = 0; + unsigned int state = 0; + unsigned int firstcompress = 0; + unsigned int where; + unsigned char ch; + char name[255]; + unsigned int namelen = 0; + + for (;;) { + if (pos >= len) goto PROTO; ch = buf[pos++]; + if (++loop >= 1000) goto PROTO; + + if (state) { + if (namelen + 1 > sizeof name) goto PROTO; name[namelen++] = ch; + --state; + } + else { + while (ch >= 192) { + where = ch; where -= 192; where <<= 8; + if (pos >= len) goto PROTO; ch = buf[pos++]; + if (!firstcompress) firstcompress = pos; + pos = where + ch; + if (pos >= len) goto PROTO; ch = buf[pos++]; + if (++loop >= 1000) goto PROTO; + } + if (ch >= 64) goto PROTO; + if (namelen + 1 > sizeof name) goto PROTO; name[namelen++] = ch; + if (!ch) break; + state = ch; + } + } + + if (!dns_domain_copy(d,name)) return 0; + + if (firstcompress) return firstcompress; + return pos; + + PROTO: + errno = error_proto; + return 0; +} -- cgit v1.2.3