Run command when gdb breakpoint is hit

I need to analyse a large pcap file and find problematic packets, so I want gdb automatically outputs packet index when error occurs. Below are the gdb commands:

(gdb) b packet.c:1430
Breakpoint 2 at 0x7ffff0f910aa: file packet.c, line 1430.
(gdb) commands
Type commands for breakpoint(s) 2, one per line.
End with a line saying just "end".
>silent
>frame 10
>printf "frame.number == %zu ||\n", packet_index
>c
>end
(gdb) r

Or you put them in a script:

b packet.c:1430
commands
 silent
 frame 10
 printf "frame.number == %zu ||\n", packet_index
 c
end

And it should be handy to log the output for checking later:

(gdb) set logging on