l_genl class has nice ways of discovering and requesting families. The
genl functionality has been added after the iwmon skeleton was created,
but it is now time to migrate to using these APIs.
This fixes a build break on some systems, specifically the
raspberry Pi 3 (ARM):
monitor/main.c: In function ‘open_packet’:
monitor/main.c:176:3: error: implicit declaration of function ‘close’; did you mean ‘pclose’? [-Werror=implicit-function-declaration]
176 | close(fd);
| ^~~~~
| pclose
To support multiple nlmon sources, move the logic that reads from iwmon
device into main.c instead of nlmon. nlmon.c now becomes agnostic of
how the packets are actually obtained. Packets are fed in via
high-level APIs such as nlmon_print_rtnl, nlmon_print_genl,
nlmon_print_pae.
The -F option is undocumented but allows you to pass a nl80211
family ID so iwmon doesn't ignore messages which don't match the
systems nl80211 family ID (i.e. pcaps from other systems).
This is somewhat of a pain to use since its unclear what the other
system's family ID actually is until you run it though something
like wireshark. Instead iwmon can ignore the family ID when in
read mode which makes reading other systems pcap files automatic.
Expand nlmon_create to be useful for both pcaps and monitoring. Doing
this also lets iwmon filter pcaps based on --no-ies,rtnl,scan etc
flags since they are part of the config.
Commit c7640f8346 was meant to fix a sign compare warning
in clang because NLMSG_NEXT internally compares the length
with nlmsghdr->nlmsg_len which is a u32. The problem is the
NLMSG_NEXT can underflow an unsigned value, hence why it
expects an int type to be passed in.
To work around this we can instead pass a larger sized
int64_t which the compiler allows since it can upgrade the
unsigned nlmsghdr->nlmsg_len. There is no underflow risk
with an int64_t either because the buffer used is much
smaller than what can fit in an int64_t.
Fixes: c7640f8346 ("monitor: fix integer comparison error (clang)")
To help understand scanning results a bit better and cut down on scan
output add an option to not print the contents of the IEs. Only the
SSID IE will be printed.
==24195== Syscall param socketcall.sendto(msg) points to uninitialised byte(s)
==24195== at 0x4F3DBEF: sendto (in /lib64/libc-2.26.so)
==24195== by 0x13A453: can_write_data (netlink.c:119)
==24195== by 0x13866B: io_callback (io.c:149)
==24195== by 0x137365: l_main_iterate (main.c:389)
==24195== by 0x1374A3: l_main_run (main.c:436)
==24195== by 0x113524: main (main.c:832)
==24195== Address 0x5205f99 is 57 bytes inside a block of size 88 alloc'd
==24195== at 0x4C2D0AF: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==24195== by 0x133931: l_malloc (util.c:62)
==24195== by 0x13AEF3: l_netlink_send (netlink.c:411)
==24195== by 0x112351: rtm_interface_send_message (main.c:276)
==24195== by 0x1126F3: iwmon_interface_lookup (main.c:405)
==24195== by 0x11351F: main (main.c:830)
==24195== Uninitialised value was created by a heap allocation
==24195== at 0x4C2D0AF: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==24195== by 0x133931: l_malloc (util.c:62)
==24195== by 0x11217B: rtm_interface_send_message (main.c:234)
==24195== by 0x1126F3: iwmon_interface_lookup (main.c:405)
==24195== by 0x11351F: main (main.c:830)
==23290== Invalid read of size 4
==23290== at 0x12D334: timeout_destroy (timeout.c:61)
==23290== by 0x12CDD1: l_main_exit (main.c:466)
==23290== by 0x111F3B: main (main.c:835)
==23290== Address 0x5211d80 is 0 bytes inside a block of size 32 free'd
==23290== at 0x4C2E1BB: free (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==23290== by 0x111F36: main (main.c:833)
==23290== Block was alloc'd at
==23290== at 0x4C2CF8F: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==23290== by 0x12A74D: l_malloc (util.c:62)
==23290== by 0x12D40F: timeout_create_with_nanoseconds (timeout.c:135)
==23290== by 0x112A31: signal_handler (main.c:661)
==23290== by 0x12D03A: signal_callback (signal.c:82)
==23290== by 0x12CC6D: l_main_iterate (main.c:387)
==23290== by 0x12CD3B: l_main_run (main.c:434)
==23290== by 0x1121F2: main (main.c:821)
==23290==
==23290== Invalid read of size 8
==23290== at 0x12D33B: timeout_destroy (timeout.c:64)
==23290== by 0x12CDD1: l_main_exit (main.c:466)
==23290== by 0x111F3B: main (main.c:835)
==23290== Address 0x5211d90 is 16 bytes inside a block of size 32 free'd
==23290== at 0x4C2E1BB: free (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==23290== by 0x111F36: main (main.c:833)
==23290== Block was alloc'd at
==23290== at 0x4C2CF8F: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==23290== by 0x12A74D: l_malloc (util.c:62)
==23290== by 0x12D40F: timeout_create_with_nanoseconds (timeout.c:135)
==23290== by 0x112A31: signal_handler (main.c:661)
==23290== by 0x12D03A: signal_callback (signal.c:82)
==23290== by 0x12CC6D: l_main_iterate (main.c:387)
==23290== by 0x12CD3B: l_main_run (main.c:434)
==23290== by 0x1121F2: main (main.c:821)
==23290==
==23290== Invalid write of size 4
==23290== at 0x12D33F: timeout_destroy (timeout.c:62)
==23290== by 0x12CDD1: l_main_exit (main.c:466)
==23290== by 0x111F3B: main (main.c:835)
==23290== Address 0x5211d80 is 0 bytes inside a block of size 32 free'd
==23290== at 0x4C2E1BB: free (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==23290== by 0x111F36: main (main.c:833)
==23290== Block was alloc'd at
==23290== at 0x4C2CF8F: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==23290== by 0x12A74D: l_malloc (util.c:62)
==23290== by 0x12D40F: timeout_create_with_nanoseconds (timeout.c:135)
==23290== by 0x112A31: signal_handler (main.c:661)
==23290== by 0x12D03A: signal_callback (signal.c:82)
==23290== by 0x12CC6D: l_main_iterate (main.c:387)
==23290== by 0x12CD3B: l_main_run (main.c:434)
==23290== by 0x1121F2: main (main.c:821)
Kernel v4.10 and later no longer export GENL_ID_GENERATE (which was
defined as 0). iwd was using this symbol to check for unmodified local
values rather than to ask for a dynamically generated netlink ID anyway,
so it makes sense to use the value 0 directly. This will work with
kernels before and after the GENL_ID_GENERATE change.
Memory allocated l_timeout struct from l_timeout_create not being
freed.
==4184== HEAP SUMMARY:
==4184== in use at exit: 32 bytes in 1 blocks
==4184== total heap usage: 50 allocs, 49 frees, 39,902 bytes allocated
==4184==
==4184== 32 bytes in 1 blocks are definitely lost in loss record 1 of 1
==4184== at 0x4C2ABA0: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==4184== by 0x40706D: l_malloc (util.c:62)
==4184== by 0x408D9A: l_timeout_create (timeout.c:117)
==4184== by 0x40896A: signal_callback (signal.c:82)
==4184== by 0x408692: l_main_run (main.c:346)
==4184== by 0x402474: main (main.c:797)
==4184==
==4184== LEAK SUMMARY:
==4184== definitely lost: 32 bytes in 1 blocks
==4184== indirectly lost: 0 bytes in 0 blocks
==4184== possibly lost: 0 bytes in 0 blocks
==4184== still reachable: 0 bytes in 0 blocks
==4184== suppressed: 0 bytes in 0 blocks
Send a RTM_DELLINK for the interface in use if it was created by iwmon.
As the main loop needs to be running when sending RTM_DELLINK, add a
timeout function for quitting the main loop.
On startup, request a list of interfaces via netlink. Find out whether
an interface of type nlmon exists and use it if it has all the needed
flags set. The default name of the interface is 'nlmon', which can be
changed from the command line. If the interface name is in use and is
not an nlmon type, print out an error message and exit.
