Hi, while reviewing Paolo's dnsproxy patches last week I noticed that we were not caching DNS TCP packets at all. Fortunately the issue has not caused any problems, we just have not cached the TCP queries but always asked them from the upstream nameserver. Following patches fixes this issue.
Patch #1 sets the MSG_NOSIGNAL flag when sending data. The flag is only used in TCP and it makes the socket to return EPIPE instead of raising SIGPIPE. The SIGPIPE caused aborts in connman even if we were catching it. Patch #2 and #3 save the packet into cache in TCP format. This way we do not need to know if the cached packet was from UDP or TCP query. When sending UDP DNS response, we just skip the first two bytes in the cached message. Patch #4 checks the cache for TCP packets properly (TCP offset is correctly verified). Patch #5 adds more debugging into code, this was usefull when figuring out the problems in DNS caching. Patch #6 checks various values from DNS packet using domain_header struct instead of directly poking the message bytes. Patch #7 checks the DNS cache before creating TCP connections to upstream nameservers. This works now the same way as UDP caching. Cheers, Jukka Jukka Rissanen (7): dnsproxy: Do not generate SIGPIPE dnsproxy: Save DNS packet in cache always in TCP format dnsproxy: Fix the negative caching of AAAA record dnsproxy: Check cache properly for TCP packets dnsproxy: Added more debugging prints dnsproxy: Use DNS header in checks dnsproxy: Check cache for TCP request before connecting to server src/dnsproxy.c | 179 ++++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 140 insertions(+), 39 deletions(-) -- 1.7.9.5 _______________________________________________ connman mailing list connman@connman.net http://lists.connman.net/listinfo/connman
