socket/SOL: sync the SOL index with linux

[anchao]

Summary

socket/SOL: sync the SOL index with linux

Testing

CI check is enough

[acassis]

@PetervdPerk-NXP Could you please review?

[PetervdPerk-NXP]

Looks good to me, psock_getsockopt works with a switch case so shouldn't pose any problems.

[yamt]

@anchao is there any benefit to be "sync" with linux?

[yamt]

i suspect dense numbers are easier for compilers to optimize switch statements.

[anchao]

@anchao is there any benefit to be "sync" with linux?

Unsynchronized options will cause some compatibility issues,
for example:

setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq));

int psock_setsockopt(FAR struct socket *psock, int level, int option,
                     FAR const void *value, socklen_t value_len)
...
      case SOL_IP:    <-- 
        ret = ipv4_setsockopt(psock, option, value, value_len);
        break;
....

this option configure will be failure since IPPROTO_IP and SOL_IP are different definitions in NuttX,
if we want to be fully compatible with posix applications, the experience of adopting Linux will be a good choice.

[yamt]

ok. sync with IPPROTO_ makes sense.
actually, shouldn't we just remove all SOL_ constants except SOL_SOCKET, and use IPPROTO_ constants instead?

[anchao]

ok. sync with IPPROTO_ makes sense.
actually, shouldn't we just remove all SOL_ constants except SOL_SOCKET, and use IPPROTO_ constants instead?

Done, please help to review the following PR:
#1320
apache/nuttx-apps#311

[jerpelea]

LGTM