getnameinfo() crashing smol_pkts

[svaniksharma]

There's this error happening where getnameinfo() crashes the program. I'm not sure precisely where it originates from, but it appears to be from the getnameinfo() internals. I've tried using a host_map linked list to save us from making too many DNS requests on the network, but to no avail.

[svaniksharma]

The following is a trace obtained from lldb:

thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGABRT
  * frame #0: 0x00007fff66af67fa libsystem_kernel.dylib`__pthread_kill + 10
    frame #1: 0x00007fff66bb3bc1 libsystem_pthread.dylib`pthread_kill + 432
    frame #2: 0x00007fff66a7da1c libsystem_c.dylib`abort + 120
    frame #3: 0x00007fff66b73647 libsystem_malloc.dylib`malloc_vreport + 548
    frame #4: 0x00007fff66b84d3f libsystem_malloc.dylib`malloc_zone_error + 183
    frame #5: 0x00007fff66b6b179 libsystem_malloc.dylib`tiny_free_list_add_ptr + 1233
    frame #6: 0x00007fff66b68274 libsystem_malloc.dylib`tiny_malloc_from_free_list + 1588
    frame #7: 0x00007fff66b67656 libsystem_malloc.dylib`tiny_malloc_should_clear + 272
    frame #8: 0x00007fff66b662ae libsystem_malloc.dylib`szone_malloc_should_clear + 66
    frame #9: 0x00007fff66b6506a libsystem_malloc.dylib`malloc_zone_malloc + 104
    frame #10: 0x00007fff66b64fe5 libsystem_malloc.dylib`malloc + 21
    frame #11: 0x00007fff66a98ca2 libsystem_dnssd.dylib`create_hdr + 93
    frame #12: 0x00007fff66a9a097 libsystem_dnssd.dylib`DNSServiceRefDeallocate + 139
    frame #13: 0x00007fff66ab62f4 libsystem_info.dylib`_mdns_query_clear + 116
    frame #14: 0x00007fff66ab4056 libsystem_info.dylib`_mdns_search_ex + 5174
    frame #15: 0x00007fff66ab9dc0 libsystem_info.dylib`mdns_hostbyaddr + 880
    frame #16: 0x00007fff66ab981a libsystem_info.dylib`si_host_byaddr + 122
    frame #17: 0x00007fff66ab9929 libsystem_info.dylib`search_host_byaddr + 249
    frame #18: 0x00007fff66ab981a libsystem_info.dylib`si_host_byaddr + 122
    frame #19: 0x00007fff66aafcd4 libsystem_info.dylib`si_nameinfo + 1332
    frame #20: 0x00007fff66aaf5af libsystem_info.dylib`_getnameinfo_interface_internal + 223
    frame #21: 0x00007fff66aaf4bf libsystem_info.dylib`getnameinfo + 175
    frame #22: 0x00000001000019a2 smol_pkts`resolve_name(ip_str="192.168.1.255") at hostname_resolution.c:18:7
    frame #23: 0x00000001000013f4 smol_pkts`print_ip_addr(addr=4278298816, end=" ") at pkt.c:215:16
    frame #24: 0x000000010000134a smol_pkts`process_ip(data="E") at pkt.c:162:3
    frame #25: 0x0000000100001302 smol_pkts`process_ether(data="������\x8c\x85\x90\x9b�) at pkt.c:155:3
    frame #26: 0x00000001000011d8 smol_pkts`process_pkt(bytes_read=76, data="\x14Y2^�) at pkt.c:137:5
    frame #27: 0x00000001000010d7 smol_pkts`event_loop(device_name="en0") at pkt.c:115:7
    frame #28: 0x0000000100001b7c smol_pkts`main(argc=3, argv=0x00007ffeefbff598) at smol_pkts.c:36:3
    frame #29: 0x00007fff669af7fd libdyld.dylib`start + 1
    frame #30: 0x00007fff669af7fd libdyld.dylib`start + 1

As you can see, getnameinfo()'s internals appear to cause the crash.