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VPP-1283: IPv6 PMTU missing MTU value in ICMP6 message.

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Fix GRE/IPv6 setting of ip->payload_length (which has never worked).

Change-Id: Ie68f1cc7bbb70489d6ec97356132c783f2345e1e
Signed-off-by: Ole Troan <ot@cisco.com>
This commit is contained in:
Ole Troan
2018-05-23 11:21:42 +02:00
committed by Florin Coras
parent 8a9c8f1412
commit da6e11b47d
4 changed files with 43 additions and 25 deletions
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4
src/vnet/gre/gre.c
View File

@ -292,8 +292,8 @@ gre6_fixup (vlib_main_t * vm,
/* Fixup the payload length field in the GRE tunnel encap that was applied
* at the midchain node */
ip0->payload_length =
clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0))
- sizeof (*ip0);
clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0) -
sizeof (*ip0));
}
void

6
src/vnet/ip/icmp6.c
View File

@ -526,13 +526,15 @@ ip6_icmp_error (vlib_main_t * vm,
b->current_length = 0;
}
}
p0->current_length =
p0->current_length > 1280 ? 1280 : p0->current_length;
/* Add IP header and ICMPv6 header including a 4 byte data field */
vlib_buffer_advance (p0,
-sizeof (ip6_header_t) -
sizeof (icmp46_header_t) - 4);
p0->current_length =
p0->current_length > 1280 ? 1280 : p0->current_length;
out_ip0 = vlib_buffer_get_current (p0);
icmp0 = (icmp46_header_t *) & out_ip0[1];

42
src/vnet/ip/ip6_forward.c
View File

@ -1561,6 +1561,19 @@ typedef enum
*/
#define IP6_MCAST_ADDR_MASK 0xffffffff
always_inline void
ip6_mtu_check (vlib_buffer_t * b, u16 packet_bytes,
u16 adj_packet_bytes, u32 * next, u32 * error)
{
if (adj_packet_bytes >= 1280 && packet_bytes > adj_packet_bytes)
{
*error = IP6_ERROR_MTU_EXCEEDED;
icmp6_error_set_vnet_buffer (b, ICMP6_packet_too_big, 0,
adj_packet_bytes);
*next = IP6_REWRITE_NEXT_ICMP_ERROR;
}
}
always_inline uword
ip6_rewrite_inline (vlib_main_t * vm,
vlib_node_runtime_t * node,
@ -1706,16 +1719,14 @@ ip6_rewrite_inline (vlib_main_t * vm,
}
/* Check MTU of outgoing interface. */
error0 =
(vlib_buffer_length_in_chain (vm, p0) >
adj0[0].
rewrite_header.max_l3_packet_bytes ? IP6_ERROR_MTU_EXCEEDED :
error0);
error1 =
(vlib_buffer_length_in_chain (vm, p1) >
adj1[0].
rewrite_header.max_l3_packet_bytes ? IP6_ERROR_MTU_EXCEEDED :
error1);
ip6_mtu_check (p0, clib_net_to_host_u16 (ip0->payload_length) +
sizeof (ip6_header_t),
adj0[0].rewrite_header.max_l3_packet_bytes,
&next0, &error0);
ip6_mtu_check (p1, clib_net_to_host_u16 (ip1->payload_length) +
sizeof (ip6_header_t),
adj1[0].rewrite_header.max_l3_packet_bytes,
&next1, &error1);
/* Don't adjust the buffer for hop count issue; icmp-error node
* wants to see the IP headerr */
@ -1849,14 +1860,13 @@ ip6_rewrite_inline (vlib_main_t * vm,
}
/* Check MTU of outgoing interface. */
error0 =
(vlib_buffer_length_in_chain (vm, p0) >
adj0[0].
rewrite_header.max_l3_packet_bytes ? IP6_ERROR_MTU_EXCEEDED :
error0);
ip6_mtu_check (p0, clib_net_to_host_u16 (ip0->payload_length) +
sizeof (ip6_header_t),
adj0[0].rewrite_header.max_l3_packet_bytes,
&next0, &error0);
/* Don't adjust the buffer for hop count issue; icmp-error node
* wants to see the IP headerr */
* wants to see the IP header */
if (PREDICT_TRUE (error0 == IP6_ERROR_NONE))
{
p0->current_data -= rw_len0;

16
test/test_mtu.py
View File

@ -165,16 +165,22 @@ class TestMTU(VppTestCase):
self.validate(reass_pkt, p4_reply)
'''
# Reset MTU
self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, current_mtu)
self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index,
current_mtu + mtu_offset)
@unittest.skip("Enable when IPv6 fragmentation is added")
def test_ip6_mtu(self):
""" IP6 MTU test """
#
# TODO: Link MTU is 216 bytes 'off'. Fix when L3 MTU patches committed
#
mtu_offset = 216
current_mtu = self.get_mtu(self.pg1.sw_if_index)
current_mtu -= mtu_offset
p_ether = Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
p_ip6 = IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6)
current_mtu = self.get_mtu(self.pg1.sw_if_index)
p_payload = UDP(sport=1234, dport=1234) / self.payload(
current_mtu - 40 - 8)
@ -186,8 +192,8 @@ class TestMTU(VppTestCase):
self.validate(p[1], p6_reply)
# MTU (only checked on encap)
self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, 1280)
self.assertEqual(1280, self.get_mtu(self.pg1.sw_if_index))
self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, 1280 + mtu_offset)
self.assertEqual(1280, self.get_mtu(self.pg1.sw_if_index) - mtu_offset)
# Should fail. Too large MTU
p_icmp6 = ICMPv6PacketTooBig(mtu=1280, cksum=0x4c7a)