ip: Fixes for IPv6 and MPLS fragmentation
Type: fix
- IPv6 fragmentation did not work if the packet spaneed multiple buffers, because the 'len' calculation to did max out at the size of a buffer
- IPv6 fragmentation did not work when the l2unfragmentable size was non-zero, it was not used in the correct places
- IPv6oMPLS fragmentation would fragment all IPv6, it should do so only for link local
- IPv6oMPLS should send back TooBig ICMP6 for non locally generated
Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: Ie8f02cdfdd7b7e8474e62b6d0acda8f20c371184
diff --git a/src/vnet/ip/ip_frag.c b/src/vnet/ip/ip_frag.c
index b9bc90d..9c223c3 100644
--- a/src/vnet/ip/ip_frag.c
+++ b/src/vnet/ip/ip_frag.c
@@ -25,10 +25,10 @@
typedef struct
{
- u8 ipv6;
u16 mtu;
u8 next;
u16 n_fragments;
+ u16 pkt_size;
} ip_frag_trace_t;
static u8 *
@@ -37,8 +37,8 @@
CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
ip_frag_trace_t *t = va_arg (*args, ip_frag_trace_t *);
- s = format (s, "IPv%s mtu: %u fragments: %u next: %d",
- t->ipv6 ? "6" : "4", t->mtu, t->n_fragments, t->next);
+ s = format (s, "mtu: %u pkt-size: %u fragments: %u next: %d", t->mtu,
+ t->pkt_size, t->n_fragments, t->next);
return s;
}
@@ -286,7 +286,7 @@
ip_frag_trace_t *tr =
vlib_add_trace (vm, node, p0, sizeof (*tr));
tr->mtu = mtu;
- tr->ipv6 = is_ip6 ? 1 : 0;
+ tr->pkt_size = vlib_buffer_length_in_chain (vm, p0);
tr->n_fragments = vec_len (buffer);
tr->next = vnet_buffer (p0)->ip_frag.next_index;
}
@@ -385,13 +385,17 @@
ip6_header_t *ip6;
u16 len, max, rem, ip_frag_id;
u8 *org_from_packet;
+ u16 head_bytes;
from_b = vlib_get_buffer (vm, from_bi);
org_from_packet = vlib_buffer_get_current (from_b);
ip6 = vlib_buffer_get_current (from_b) + l2unfragmentablesize;
+ head_bytes =
+ (sizeof (ip6_header_t) + sizeof (ip6_frag_hdr_t) + l2unfragmentablesize);
rem = clib_net_to_host_u16 (ip6->payload_length);
- max = (mtu - sizeof (ip6_header_t) - sizeof (ip6_frag_hdr_t)) & ~0x7; // TODO: Is max correct??
+ max = (clib_min (mtu, vlib_buffer_get_default_data_size (vm)) - head_bytes) &
+ ~0x7;
if (rem >
(vlib_buffer_length_in_chain (vm, from_b) - sizeof (ip6_header_t)))
@@ -423,9 +427,7 @@
ip6_frag_hdr_t *to_frag_hdr;
u8 *to_data;
- len =
- (rem >
- (mtu - sizeof (ip6_header_t) - sizeof (ip6_frag_hdr_t)) ? max : rem);
+ len = (rem > max ? max : rem);
if (len != rem) /* Last fragment does not need to divisible by 8 */
len &= ~0x7;
if ((to_b = frag_buffer_alloc (org_from_b, &to_bi)) == 0)
@@ -438,7 +440,7 @@
/* Copy ip6 header */
clib_memcpy_fast (to_b->data, org_from_packet,
l2unfragmentablesize + sizeof (ip6_header_t));
- to_ip6 = vlib_buffer_get_current (to_b);
+ to_ip6 = vlib_buffer_get_current (to_b) + l2unfragmentablesize;
to_frag_hdr = (ip6_frag_hdr_t *) (to_ip6 + 1);
to_data = (void *) (to_frag_hdr + 1);
@@ -484,8 +486,7 @@
to_ptr += bytes_to_copy;
}
- to_b->current_length =
- len + sizeof (ip6_header_t) + sizeof (ip6_frag_hdr_t);
+ to_b->current_length = len + head_bytes;
to_ip6->payload_length =
clib_host_to_net_u16 (len + sizeof (ip6_frag_hdr_t));
to_ip6->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
diff --git a/src/vnet/mpls/mpls_output.c b/src/vnet/mpls/mpls_output.c
index 3699163..faeba74 100644
--- a/src/vnet/mpls/mpls_output.c
+++ b/src/vnet/mpls/mpls_output.c
@@ -377,11 +377,12 @@
typedef enum
{
- MPLS_FRAG_NEXT_REWRITE,
- MPLS_FRAG_NEXT_REWRITE_MIDCHAIN,
- MPLS_FRAG_NEXT_ICMP_ERROR,
- MPLS_FRAG_NEXT_DROP,
- MPLS_FRAG_N_NEXT,
+ MPLS_FRAG_NEXT_REWRITE,
+ MPLS_FRAG_NEXT_REWRITE_MIDCHAIN,
+ MPLS_FRAG_NEXT_ICMP4_ERROR,
+ MPLS_FRAG_NEXT_ICMP6_ERROR,
+ MPLS_FRAG_NEXT_DROP,
+ MPLS_FRAG_N_NEXT,
} mpls_frag_next_t;
static uword
@@ -390,9 +391,7 @@
vlib_frame_t * frame)
{
u32 n_left_from, next_index, * from, * to_next, n_left_to_next, *frags;
- vlib_node_runtime_t * error_node;
- error_node = vlib_node_get_runtime (vm, mpls_output_node.index);
from = vlib_frame_vector_args (frame);
n_left_from = frame->n_vectors;
next_index = node->cached_next_index;
@@ -410,8 +409,7 @@
mpls_frag_next_t next0;
u32 pi0, adj_index0;
ip_frag_error_t error0 = IP_FRAG_ERROR_NONE;
- i16 encap_size;
- u16 mtu;
+ i16 encap_size, mtu;
u8 is_ip4;
pi0 = to_next[0] = from[0];
@@ -422,6 +420,7 @@
adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
adj0 = adj_get (adj_index0);
+
/* the size of the MPLS stack */
encap_size = vnet_buffer (p0)->l3_hdr_offset - p0->current_data;
mtu = adj0->rewrite_header.max_l3_packet_bytes - encap_size;
@@ -430,7 +429,18 @@
if (is_ip4)
error0 = ip4_frag_do_fragment (vm, pi0, mtu, encap_size, &frags);
else
- error0 = ip6_frag_do_fragment (vm, pi0, mtu, encap_size, &frags);
+ {
+ if (!(p0->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED))
+ {
+ /* only fragment locally generated IPv6 */
+ error0 = IP_FRAG_ERROR_DONT_FRAGMENT_SET;
+ }
+ else
+ {
+ error0 =
+ ip6_frag_do_fragment (vm, pi0, mtu, encap_size, &frags);
+ }
+ }
if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
{
@@ -443,24 +453,41 @@
if (PREDICT_TRUE (error0 == IP_FRAG_ERROR_NONE))
{
/* Free original buffer chain */
- vlib_buffer_free_one (vm, pi0); /* Free original packet */
+ vlib_buffer_free_one (vm, pi0);
next0 = (IP_LOOKUP_NEXT_MIDCHAIN == adj0->lookup_next_index ?
MPLS_FRAG_NEXT_REWRITE_MIDCHAIN :
MPLS_FRAG_NEXT_REWRITE);
}
- else if (is_ip4 && error0 == IP_FRAG_ERROR_DONT_FRAGMENT_SET)
- {
- icmp4_error_set_vnet_buffer (
- p0, ICMP4_destination_unreachable,
- ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set,
- vnet_buffer (p0)->ip_frag.mtu);
- next0 = MPLS_FRAG_NEXT_ICMP_ERROR;
- }
else
{
- vlib_error_count (vm, mpls_output_node.index, error0, 1);
- vec_add1 (frags, pi0); /* Get rid of the original buffer */
- next0 = MPLS_FRAG_NEXT_DROP;
+ vlib_error_count (vm, node->node_index, error0, 1);
+
+ if (error0 == IP_FRAG_ERROR_DONT_FRAGMENT_SET)
+ {
+ vlib_buffer_advance (p0, encap_size);
+ if (is_ip4)
+ {
+ icmp4_error_set_vnet_buffer (
+ p0, ICMP4_destination_unreachable,
+ ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set,
+ vnet_buffer (p0)->ip_frag.mtu);
+ next0 = MPLS_FRAG_NEXT_ICMP4_ERROR;
+ }
+ else
+ {
+ icmp6_error_set_vnet_buffer (
+ p0, ICMP6_packet_too_big, 0,
+ adj0->rewrite_header.max_l3_packet_bytes);
+ next0 = MPLS_FRAG_NEXT_ICMP6_ERROR;
+ }
+ }
+ else
+ {
+ next0 = MPLS_FRAG_NEXT_DROP;
+ }
+
+ /* Get rid of the original buffer */
+ vec_add1 (frags, pi0);
}
/* Send fragments that were added in the frame */
@@ -480,9 +507,6 @@
to_next += 1;
n_left_to_next -= 1;
- p0 = vlib_get_buffer (vm, i);
- p0->error = error_node->errors[error0];
-
vlib_validate_buffer_enqueue_x1 (
vm, node, next_index, to_next, n_left_to_next, i, next0);
}
@@ -511,22 +535,21 @@
}
VLIB_REGISTER_NODE (mpls_frag_node) = {
- .function = mpls_frag,
- .name = "mpls-frag",
- .vector_size = sizeof (u32),
- .format_trace = format_mpls_frag_trace,
- .type = VLIB_NODE_TYPE_INTERNAL,
+ .function = mpls_frag,
+ .name = "mpls-frag",
+ .vector_size = sizeof (u32),
+ .format_trace = format_mpls_frag_trace,
+ .type = VLIB_NODE_TYPE_INTERNAL,
- .n_errors = IP_FRAG_N_ERROR,
- .error_strings = mpls_frag_error_strings,
+ .n_errors = IP_FRAG_N_ERROR,
+ .error_strings = mpls_frag_error_strings,
- .n_next_nodes = MPLS_FRAG_N_NEXT,
- .next_nodes = {
- [MPLS_FRAG_NEXT_REWRITE] = "mpls-output",
- [MPLS_FRAG_NEXT_REWRITE_MIDCHAIN] = "mpls-midchain",
- [MPLS_FRAG_NEXT_ICMP_ERROR] = "ip4-icmp-error",
- [MPLS_FRAG_NEXT_DROP] = "mpls-drop"
- },
+ .n_next_nodes = MPLS_FRAG_N_NEXT,
+ .next_nodes = { [MPLS_FRAG_NEXT_REWRITE] = "mpls-output",
+ [MPLS_FRAG_NEXT_REWRITE_MIDCHAIN] = "mpls-midchain",
+ [MPLS_FRAG_NEXT_ICMP4_ERROR] = "ip4-icmp-error",
+ [MPLS_FRAG_NEXT_ICMP6_ERROR] = "ip6-icmp-error",
+ [MPLS_FRAG_NEXT_DROP] = "mpls-drop" },
};
/*