[PATCH gwproxy v7 0/2] Initial work on integration of DNS parser lib in gwproxy

[Ahmad Gani <reyuki@gnuweeb.org>]

Hi Chief,

This is revision v7 of the initial work on the integration of the DNS
parser lib in gwproxy. This is an RFC draft; the patches themselves
aren't final.

There are 2 patches in this series:
- refactor gwproxy codebase (specifically, DNS system)
- add dns parser code

Thanks for taking a look.

# Changelog
v1 -> v2:
- use existing convert_str_to_ssaddr instead of init_addr
- fix memory leak when init_addr (now it's replaced) failed
- modify convert_str_to_ssaddr to support default port
- bring back __cold attribute on convert_ssaddr_to_str
- don't fill a dangling pointer as Sir Alviro said
- for now it's blocking, attempt_retry label is not needed

v2 -> v3:
- remove TODO(reyuki): hints->ai_family is used to filter results
- make gw_ares_getaddrinfo asynchronous by change UDP socket to non-blocking
- move socket creation to library initialization
- make UDP socket unconnected
- restructure internal struct and program execution flow to support async
- update unit test of dns parser
- transaction id creation is delegated to caller
- fix logic bug in serialize_answ that can lead to memory error: invalid read
- rename parameter prt and split commit message
- move variable declaration in for loop according to the Sir Alviro coding-style

v3 -> v4:
- add else block in the convert_str_to_ssaddr function
- use format specifier %hu for uint16_t in printf
- update base commit to branch master from upstream remote repository

v4 -> v5:
- squash commits to eliminate changes unrelated to the commit subject
- change commit subject: use imperative form for the subject
- update base commit to branch master from upstream remote repository
- changing the email subject
- drop the c-ares style thing
- restructure dnsparser.c and dnsparser.h

v5 -> v6:
- mark this feature as experimental and disabled by default
- fix minor issues from master branch
- fix dns parser
- add dns server as gwproxy' cmdline option
- add fallback mechanism for raw dns backend

v6 -> v7:
- squash commits
- refactor gwproxy codebase (specifically, DNS system)
- add dns parser code

Signed-off-by: Ahmad Gani <reyuki@gnuweeb.org>
---

Ahmad Gani (2):
  dnsparser: Add dns parser code
  gwproxy: refactor code base to add experimental raw DNS backend

 Makefile                |   2 +-
 configure               |   8 +
 src/gwproxy/dns.c       | 240 +++++++++++++++--
 src/gwproxy/dns.h       |  29 +-
 src/gwproxy/dnsparser.c | 581 ++++++++++++++++++++++++++++++++++++++++
 src/gwproxy/dnsparser.h | 192 +++++++++++++
 src/gwproxy/ev/epoll.c  |  69 ++++-
 src/gwproxy/gwproxy.c   |  54 +++-
 src/gwproxy/gwproxy.h   |   5 +-
 9 files changed, 1131 insertions(+), 49 deletions(-)
 create mode 100644 src/gwproxy/dnsparser.c
 create mode 100644 src/gwproxy/dnsparser.h


base-commit: b2a7a2d33ba8676d917fd26fc3a86bdde8961d76
-- 
Ahmad Gani