compile with Sun C, as "interface.h" isn't being included before the
structures are being declared.
Furthermore, in the files that Sun C *can* compile, it doesn't cause Sun
C to generate code that's safe with unaligned accesses, as
"__attribute__" is defined as a do-nothing macro with compilers that
don't support it.
Therefore, we get rid of that tag on the structures to which it was
added, and instead use "EXTRACT_16BIT()" and "EXTRACT_32BIT()" to fetch
16-bit and 32-bit big-endian quantities from packets. We also fix some
other references to multi-byte quantities to get rid of code that tries
to do unaligned loads on platforms that don't support them.
We also throw in a hack that makes those macros use
"__attribute__((packed))" on structures containing only one 16-bit or
32-bit integer to get the compiler to generate unaligned-safe code
rather than doing it by hand. (GCC on SPARC produces the same code that
doing it by hand does; I don't know if GCC on any other big-endian
strict-alignment processor generates better code for that case. On
little-endian processors, as "ntohs()" and "ntohl()" might be functions,
that might actually produce worse code.)
Fix some places to use "%u" rather than "%d" to print unsigned
quantities.
at the end of the link-layer header; put it there.
Put in a comment indicating that the layout of the link-layer header
shouldn't be changed; if a new header is necessary, a new DLL_ type
should be introduced for it.
them in "print-sll.c" - as a cooked-mode capture may be reading from
non-Ethernet, non-802.x devices, it may well see some
ETH_P_/LINUX_SLL_P_ types that don't mean "this is an 802.2 LLC frame".
We currently assume that the ETH_P_ values won't change in the kernel,
so we don't have to explicitly map them.
In various link-layer packet printers, if we don't handle the next layer
up of packet type, and are printing the link-layer header, use the
correct pointer to that header (i.e., if we've stepped "p" past the
link-layer header, don't use "p", use a pointer to the beginning of the
packet), and use the correct length (i.e., if we've subtracted the
length of the link-layer header, add it back in, so that we always print
the full packet length).
live captures with a "cooked" (SOCK_DGRAM) rather than a "raw"
(SOCK_RAW) PF_PACKET socket; it includes a bunch of the fields from the
"struct sockaddr_ll" you get in a "recvfrom()", including the Ethernet
protocol field.
