diff options
Diffstat (limited to 'src/network/dns_parse.c')
-rw-r--r-- | src/network/dns_parse.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/src/network/dns_parse.c b/src/network/dns_parse.c new file mode 100644 index 00000000..aa0d39f3 --- /dev/null +++ b/src/network/dns_parse.c @@ -0,0 +1,31 @@ +#include <string.h> + +int __dns_parse(const unsigned char *r, int rlen, int (*callback)(void *, int, const void *, int, const void *), void *ctx) +{ + int qdcount, ancount; + const unsigned char *p; + int len; + + if ((r[3]&15)) return 0; + p = r+12; + qdcount = r[4]*256 + r[5]; + ancount = r[6]*256 + r[7]; + if (qdcount+ancount > 64) return -1; + while (qdcount--) { + while (p-r < rlen && *p-1U < 127) p++; + if (*p>193 || (*p==193 && p[1]>254) || p>r+506) + return -1; + p += 5 + !!*p; + } + while (ancount--) { + while (p-r < rlen && *p-1U < 127) p++; + if (*p>193 || (*p==193 && p[1]>254) || p>r+506) + return -1; + p += 1 + !!*p; + len = p[8]*256 + p[9]; + if (p+len > r+rlen) return -1; + if (callback(ctx, p[1], p+10, len, r) < 0) return -1; + p += 10 + len; + } + return 0; +} |