[lwip-devel] Summary of changes after porting to Linux and Hurd

[Joan Lledó]

Hello lwip,

I recently updated the lwip debian package for the Hurd and Linux to 2.1.2, and 
during
the process I found some issues I'd like to fix, if you agree:

1.- include/lwip/if_api.h: IF_NAMESIZE could be defined by external socket 
headers, so
    it should be defined only if it's not defined before.

2.- contrib/ports/unix/lib/lwipopts.h: sys_check_core_locking() and pals are 
declared
    in lwipopts.h, is this the proper place? why aren't they declared in 
sys_arch.h?

3.- contrib/ports/unix/port/sys_arch.c: sys_arch_sem_wait() and cond_wait():
    - On the Hurd, pthread_cond_wait() and pthread_cond_timedwait() are 
awakened when
      glibc cancels the RPC that called them. I wrote some code to handle this 
case.
  - contrib/ports/unix/port/include/arch/sys_arch.h: I defined SYS_ARCH_INTR to 
be
    returned by sys_arch_sem_wait() when pthread_cond_wait() was awakened on 
the Hurd.

4.- contrib/ports/unix/check/CMakeLists.txt: Add support for the Hurd:
  - Line 7: add AND NOT CMAKE_SYSTEM_NAME STREQUAL GNU
  - Line 12: set(LWIP_USE_SANITIZERS true) only if (NOT CMAKE_SYSTEM_NAME 
STREQUAL GNU)
  - Line 48: add OR CMAKE_SYSTEM_NAME STREQUAL GNU

5.- apps/tftp/tftp.c: recv() could be declared by external socket headers. 
Rename it to
    tftp_recv()
  - Lines 243 and 471

6.- test/unit/api/test_sockets.c:
  - Line 156: write() could be declared by external socket headers. Call 
lwip_write()
    instead.
  - Line 333: it expects fcntl() to return 6, but O_RDWR could have another 
value if
    external socket headers are present. Replace 6 by O_RDWR.
  - In Linux, when using the system's sockets headers, struct 
msghdr->msg_iovlen is not
    defined as int.
    - POSIX[1] says it must be int
    - My solution was:
      - add a typedef int msg_iovlen_t; in lwip's sockets.h
      - declare msg_iovlen as msg_iovlen_t inside struct msghdr in lwip's 
sockets.h
      - let the user typedef msg_iovlen_t as the type they need for their system
      - Line 253: declare i as msg_iovlen_t i;

7.- src/api/tcpip.c:
  - New function tcpip_callback_wait() to call a function inside the tcpip 
thread
    and block the calling thread until the callback finishes.
  - I already wrote a patch[2] for this and am waiting for its review.

8.- src/apps/lwiperf/lwiperf.c:
  - Line 773: Calls htonl() but lwip/inet.h is not included
  - There are other apps and unit tests where htons and pals are being called 
w/o
    including lwip/inet.h

9.- src/include/lwip/sockets.h:
  - Lines 536 and following lines until the end: I think all definitions of the 
socket
    functions should be moved outside the #define LWIP_SOCKET_EXTERNAL_HEADERS, 
because
    a user that has set LWIP_SOCKETS to 1 will need them regardless they use 
lwip's or
    their own socket headers.
  - struct sockaddr includes sa_len, but some systems like Linux doesn't have 
this filed,
    which produces many compilation problems.
    - My solution was:
      - Create macros to write and read from sa_len/sin_len/sin6_len fields
      - Replace all occurrences this fields for the proper macro
      - Declare write macros as empty and read macros as default values on 
systems where
        sa_len and pals are not supported
      - Use _HAVE_SA_LEN to identify whether the system supports sa_len

I'll write patches for all this issues if you think they should be upstream.

Regards.

-------------------
[1] http://pubs.opengroup.org/onlinepubs/9699919799/
[2] https://savannah.nongnu.org/patch/?9807