From ec5371e3e31b7860d6b3996fd10420566a4377f2 Mon Sep 17 00:00:00 2001 From: Neale Ranns Date: Fri, 4 Mar 2022 11:45:41 +0000 Subject: 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 Change-Id: Ie8f02cdfdd7b7e8474e62b6d0acda8f20c371184 --- src/vnet/ip/ip_frag.c | 23 +++++----- src/vnet/mpls/mpls_output.c | 105 +++++++++++++++++++++++++++----------------- 2 files changed, 76 insertions(+), 52 deletions(-) (limited to 'src/vnet') diff --git a/src/vnet/ip/ip_frag.c b/src/vnet/ip/ip_frag.c index b9bc90dcc11..9c223c3d0ae 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 @@ format_ip_frag_trace (u8 * s, va_list * args) 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 @@ frag_node_inline (vlib_main_t * vm, vlib_node_runtime_t * node, 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_frag_do_fragment (vlib_main_t * vm, u32 from_bi, u16 mtu, 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_do_fragment (vlib_main_t * vm, u32 from_bi, u16 mtu, 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 @@ ip6_frag_do_fragment (vlib_main_t * vm, u32 from_bi, u16 mtu, /* 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 @@ ip6_frag_do_fragment (vlib_main_t * vm, u32 from_bi, u16 mtu, 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 3699163a155..faeba748e89 100644 --- a/src/vnet/mpls/mpls_output.c +++ b/src/vnet/mpls/mpls_output.c @@ -377,11 +377,12 @@ typedef struct mpls_frag_trace_t_ 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 @@ mpls_frag (vlib_main_t * vm, 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 (vlib_main_t * vm, 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 @@ mpls_frag (vlib_main_t * vm, 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 @@ mpls_frag (vlib_main_t * vm, 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 @@ mpls_frag (vlib_main_t * vm, 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 @@ mpls_frag (vlib_main_t * vm, 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 @@ format_mpls_frag_trace (u8 * s, va_list * args) } 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, - - .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" - }, + .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_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" }, }; /* -- cgit 1.2.3-korg