mirror of
https://github.com/freebsd/freebsd-src
synced 2024-09-06 17:18:32 +00:00
frag6: properly handle atomic fragments according to RFCs.
RFC 8200 says:
"If the fragment is a whole datagram (that is, both the Fragment
Offset field and the M flag are zero), then it does not need
any further reassembly and should be processed as a fully
reassembled packet (i.e., updating Next Header, adjust Payload
Length, removing the Fragment header, etc.). .."
That means we should remove the fragment header and make all the adjustments
rather than just skipping over the fragment header. The difference should
be noticeable in that a properly handled atomic fragment triggering an ICMPv6
message at an upper layer (e.g. dest unreach, unreachable port) will not
include the fragment header.
Update the test cases to also test for an unfragmentable part. That is
needed so that the next header is properly updated (not just lengths).
MFC after: 3 weeks
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D22155
This commit is contained in:
Bjoern A. Zeeb
parent
20cb0deaa2
commit
c1131de6f1
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=354542
|
|
@ -395,6 +395,8 @@ frag6_input(struct mbuf **mp, int *offp, int proto)
|
|||
m = *mp;
|
||||
offset = *offp;
|
||||
|
||||
M_ASSERTPKTHDR(m);
|
||||
|
||||
ip6 = mtod(m, struct ip6_hdr *);
|
||||
#ifndef PULLDOWN_TEST
|
||||
IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE);
|
||||
|
|
@ -437,23 +439,36 @@ frag6_input(struct mbuf **mp, int *offp, int proto)
|
|||
IP6STAT_INC(ip6s_fragments);
|
||||
in6_ifstat_inc(dstifp, ifs6_reass_reqd);
|
||||
|
||||
/* Offset now points to data portion. */
|
||||
offset += sizeof(struct ip6_frag);
|
||||
|
||||
/*
|
||||
* Handle "atomic" fragments (offset and m bit set to 0) upfront,
|
||||
* unrelated to any reassembly. Still need to remove the frag hdr.
|
||||
* unrelated to any reassembly. We need to remove the frag hdr
|
||||
* which is ugly.
|
||||
* See RFC 6946 and section 4.5 of RFC 8200.
|
||||
*/
|
||||
if ((ip6f->ip6f_offlg & ~IP6F_RESERVED_MASK) == 0) {
|
||||
IP6STAT_INC(ip6s_atomicfrags);
|
||||
/* XXX-BZ handle correctly. */
|
||||
nxt = ip6f->ip6f_nxt;
|
||||
/*
|
||||
* Set nxt(-hdr field value) to the original value.
|
||||
* We cannot just set ip6->ip6_nxt as there might be
|
||||
* an unfragmentable part with extension headers and
|
||||
* we must update the last one.
|
||||
*/
|
||||
m_copyback(m, ip6_get_prevhdr(m, offset), sizeof(uint8_t),
|
||||
(caddr_t)&nxt);
|
||||
ip6->ip6_plen = htons(ntohs(ip6->ip6_plen) -
|
||||
sizeof(struct ip6_frag));
|
||||
if (ip6_deletefraghdr(m, offset, M_NOWAIT) != 0)
|
||||
goto dropfrag2;
|
||||
m->m_pkthdr.len -= sizeof(struct ip6_frag);
|
||||
in6_ifstat_inc(dstifp, ifs6_reass_ok);
|
||||
*offp = offset;
|
||||
m->m_flags |= M_FRAGMENTED;
|
||||
return (ip6f->ip6f_nxt);
|
||||
*mp = m;
|
||||
return (nxt);
|
||||
}
|
||||
|
||||
/* Offset now points to data portion. */
|
||||
offset += sizeof(struct ip6_frag);
|
||||
|
||||
/* Get fragment length and discard 0-byte fragments. */
|
||||
frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
|
||||
if (frgpartlen == 0) {
|
||||
|
|
|
|||
|
|
@ -95,6 +95,33 @@ def main():
|
|||
ip6f01.display()
|
||||
sp.sendp(ip6f01, iface=args.sendif[0], verbose=False)
|
||||
|
||||
sleep(0.10)
|
||||
sniffer.setEnd()
|
||||
sniffer.join()
|
||||
if not sniffer.foundCorrectPacket:
|
||||
sys.exit(1)
|
||||
|
||||
|
||||
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # ##
|
||||
#
|
||||
# Atomic fragment with extension header.
|
||||
#
|
||||
# A: Nothing listening on UDP port.
|
||||
# R: ICMPv6 dst unreach, unreach port.
|
||||
#
|
||||
# Start sniffing on recvif
|
||||
sniffer = Sniffer(args, check_icmp6_error)
|
||||
|
||||
ip6f01 = sp.Ether() / \
|
||||
sp.IPv6(src=args.src[0], dst=args.to[0]) / \
|
||||
sp.IPv6ExtHdrDestOpt(options = \
|
||||
sp.PadN(optdata="\x00\x00\x00\x00\x00\x00")) / \
|
||||
sp.IPv6ExtHdrFragment(offset=0, m=0, id=0x3001) / \
|
||||
sp.UDP(dport=3456, sport=6543)
|
||||
if args.debug :
|
||||
ip6f01.display()
|
||||
sp.sendp(ip6f01, iface=args.sendif[0], verbose=False)
|
||||
|
||||
sleep(0.10)
|
||||
sniffer.setEnd()
|
||||
sniffer.join()
|
||||
|
|
|
|||
|
|
@ -67,12 +67,12 @@ frag6_03_check_stats() {
|
|||
# Check selection of global UDP stats.
|
||||
#
|
||||
cat <<EOF > ${HOME}/filter-${jname}.txt
|
||||
<received-datagrams>1</received-datagrams>
|
||||
<received-datagrams>2</received-datagrams>
|
||||
<dropped-incomplete-headers>0</dropped-incomplete-headers>
|
||||
<dropped-bad-data-length>0</dropped-bad-data-length>
|
||||
<dropped-bad-checksum>0</dropped-bad-checksum>
|
||||
<dropped-no-checksum>0</dropped-no-checksum>
|
||||
<dropped-no-socket>1</dropped-no-socket>
|
||||
<dropped-no-socket>2</dropped-no-socket>
|
||||
<dropped-broadcast-multicast>0</dropped-broadcast-multicast>
|
||||
<dropped-full-socket-buffer>0</dropped-full-socket-buffer>
|
||||
<not-for-hashed-pcb>0</not-for-hashed-pcb>
|
||||
|
|
@ -94,11 +94,11 @@ EOF
|
|||
<dropped-short-packets>0</dropped-short-packets>
|
||||
<dropped-bad-options>0</dropped-bad-options>
|
||||
<dropped-bad-version>0</dropped-bad-version>
|
||||
<received-fragments>1</received-fragments>
|
||||
<received-fragments>2</received-fragments>
|
||||
<dropped-fragment>0</dropped-fragment>
|
||||
<dropped-fragment-after-timeout>0</dropped-fragment-after-timeout>
|
||||
<dropped-fragments-overflow>0</dropped-fragments-overflow>
|
||||
<atomic-fragments>1</atomic-fragments>
|
||||
<atomic-fragments>2</atomic-fragments>
|
||||
<reassembled-packets>0</reassembled-packets>
|
||||
<forwarded-packets>0</forwarded-packets>
|
||||
<packets-not-forwardable>0</packets-not-forwardable>
|
||||
|
|
@ -124,12 +124,12 @@ EOF
|
|||
# XXX-TODO check output histogram (just too hard to parse [no multi-line-grep])
|
||||
#
|
||||
cat <<EOF > ${HOME}/filter-${jname}.txt
|
||||
<icmp6-calls>1</icmp6-calls>
|
||||
<icmp6-calls>2</icmp6-calls>
|
||||
<no-route>0</no-route>
|
||||
<admin-prohibited>0</admin-prohibited>
|
||||
<beyond-scope>0</beyond-scope>
|
||||
<address-unreachable>0</address-unreachable>
|
||||
<port-unreachable>1</port-unreachable>
|
||||
<port-unreachable>2</port-unreachable>
|
||||
<packet-too-big>0</packet-too-big>
|
||||
<time-exceed-transmit>0</time-exceed-transmit>
|
||||
<time-exceed-reassembly>0</time-exceed-reassembly>
|
||||
|
|
@ -170,8 +170,8 @@ EOF
|
|||
<discard-fragments>0</discard-fragments>
|
||||
<fragments-failed>0</fragments-failed>
|
||||
<fragments-created>0</fragments-created>
|
||||
<reassembly-required>1</reassembly-required>
|
||||
<reassembled-packets>1</reassembled-packets>
|
||||
<reassembly-required>2</reassembly-required>
|
||||
<reassembled-packets>2</reassembled-packets>
|
||||
<reassembly-failed>0</reassembly-failed>
|
||||
EOF
|
||||
count=`jexec ${jname} netstat -s -p ip6 -I ${ifname} --libxo xml,pretty | grep -E -x -c -f ${HOME}/filter-${jname}.txt`
|
||||
|
|
@ -196,8 +196,8 @@ EOF
|
|||
<received-echo-replies>0</received-echo-replies>
|
||||
<received-router-solicitation>0</received-router-solicitation>
|
||||
<received-router-advertisement>0</received-router-advertisement>
|
||||
<sent-errors>1</sent-errors>
|
||||
<sent-destination-unreachable>1</sent-destination-unreachable>
|
||||
<sent-errors>2</sent-errors>
|
||||
<sent-destination-unreachable>2</sent-destination-unreachable>
|
||||
<sent-admin-prohibited>0</sent-admin-prohibited>
|
||||
<sent-time-exceeded>0</sent-time-exceeded>
|
||||
<sent-bad-parameter>0</sent-bad-parameter>
|
||||
|
|
|
|||
Loading…
Reference in a new issue