libnet_build_ipv6_destopts() alters the payload #34
Description
Hi,
I have problems generating a IPv6 destination option in a packet using the libnet_build_ipv6_destopts() function.
The following test code I'm using:
t = LIBNET_PTAG_INITIALIZER;
t = libnet_build_icmpv6_echo(ICMP6_ECHO, 0, 0, 1, 0, NULL,
0, l, t);
t = libnet_build_ipv6_destopts(
IPPROTO_ICMP6,
0,
"\x80\x01\x00\x00\x00\x00",
6,
l,
0);
libnet_build_ipv6(
0,
0,
LIBNET_ICMPV6_H + LIBNET_IPV6_DESTOPTS_H,
IPPROTO_DSTOPTS,
64,
src_ip,
dst_ip,
NULL,
0,
l,
0);Before sending it via libnet_write() I dump the pblock using libnet_diag_dump_pblock() and the output is:
pblock type: unrecognized pblock
ptag number: 1
pblock address: 0x8178190
next pblock 0x81781c8 (ipv6_destopts)
prev pblock (nil)
buf: 8000000000010000
buffer length: 8
checksum flag: Yes
chksum length: 0
bytes copied: 8
pblock type: ipv6_destopts
ptag number: 2
pblock address: 0x81781c8
next pblock 0x8178200 (ipv6)
prev pblock 0x8178190 (unrecognized pblock)
buf: 3a00800100000000
buffer length: 8
checksum flag: No
bytes copied: 8
pblock type: ipv6
ptag number: 3
pblock address: 0x8178200
next pblock (nil)
prev pblock 0x81781c8 (ipv6_destopts)
buf: 60000000000a3c4020014dd0ff00842102242bfffe69c29b20014dd0ff0084210224fefffec9b185
buffer length: 40
checksum flag: No
bytes copied: 40
This looks good but the packet shows something different:
It seems that libnet_write() modifies the data passed as destination option payload.
Or do I use the function in a wrong way? I read the documentation about the function and the payload interface but couldn't find any special I'm doing wrong.