[PATCH gwproxy v2 0/3] Initial work for DNS lookup implementation

[Ahmad Gani <reyuki@gnuweeb.org>]

Hi Chief,

This is initial work of dns lookup feature, The patches aren't final, but
it's enough to get a grasp of what the interface looks like. I've 
provided a temporary entry point main function to test it.

There are 3 patches in this series:
- create net.h and net.c to store network related functionality.
- allow only port string number in service parameter of gwp_dns_queue
- initial work for implementation of C-ares-like getaddrinfo function

On Thu, 31 Jul 2025 21:01:02 +0700, Ammar Faizi wrote:
>> On Thu, Jul 31, 2025 at 10:07:44AM +0700, Ahmad Gani wrote:
>> +int init_addr(const char *addr, struct gwp_sockaddr *addr_st, uint16_t port)
> This is a no-no. We don't need it.

Sorry, I didn't know the existence of convert_str_to_ssaddr, the init_addr
is now replaced with convert_str_to_ssaddr.

> In gwproxy.c, there is convert_str_to_ssaddr(). It's also better than
> your version because with it you can have:
>
>  ./gwproxy --target google.com:80 --bind localhost:1111
> Not restricted to IP address format, but domain name is also ok.

Looking at the example, I guess I need to add logic to handle Special-use
domain name [1] and an ability to detect local name server in the system
to fully replace glibc's getaddrinfo, but since it's mentioned somewhere
in the mail threads [2] that we can use glibc's getaddrinfo for just 
bootstrapping purpose I guess I don't need to fully replace it then.

I also bring back __cold attribute on convert_ssaddr_to_str function to 
inform  the compiler that function is unlikely to be executed and thus 
change optiomization priority for size first rather than speed.

## 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 [3]
- for now it's blocking, attempt_retry label is not needed

[1]:
- https://en.wikipedia.org/wiki/Special-use_domain_name

[2]:
- https://lore.gnuweeb.org/gwml/aIu7m+NE8Iny+YQN@linux.gnuweeb.org

[3]:
- https://lore.gnuweeb.org/gwml/CAOG64qMPmFL-+7OrVv4psmyOt8G-3OZJGa=bQ1a_wuV06WTyng@mail.gmail.com/

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

Ahmad Gani (3):
  dnslookup: split common functionality and struct into net.c
  dnslookup: Allow only port string number
  dnslookup: Initial work for implementation of C-ares-like getaddrinfo
    function

 Makefile                |   1 +
 man/gwp_dns_queue.3     |   2 +-
 src/gwproxy/dns.h       |  12 +-
 src/gwproxy/dnslookup.c | 289 ++++++++++++++++++++++++++++++++
 src/gwproxy/dnslookup.h | 118 +++++++++++++
 src/gwproxy/dnsparser.c | 357 ++++++++++++++++++++++++++++++++++++++++
 src/gwproxy/dnsparser.h | 191 +++++++++++++++++++++
 src/gwproxy/gwproxy.c   |  93 +----------
 src/gwproxy/net.c       | 103 ++++++++++++
 src/gwproxy/net.h       |  35 ++++
 10 files changed, 1099 insertions(+), 102 deletions(-)
 create mode 100644 src/gwproxy/dnslookup.c
 create mode 100644 src/gwproxy/dnslookup.h
 create mode 100644 src/gwproxy/dnsparser.c
 create mode 100644 src/gwproxy/dnsparser.h
 create mode 100644 src/gwproxy/net.c
 create mode 100644 src/gwproxy/net.h


base-commit: 0753f2d766e85fcbffc1f83dfd4e67d6206591cb
-- 
Ahmad Gani