/*--------------------------------------------------------------------------- * Copyright (c) 2009-2014 Cisco and/or its affiliates. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. *--------------------------------------------------------------------------- */ /* * IPv4 Fragmentation Node * * */ #include "ip_frag.h" #include <vnet/ip/ip.h> typedef struct { u8 ipv6; u16 header_offset; u16 mtu; u8 next; u16 n_fragments; } ip_frag_trace_t; static u8 * 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 offset: %u mtu: %u fragments: %u", t->ipv6 ? "6" : "4", t->header_offset, t->mtu, t->n_fragments); return s; } static u32 running_fragment_id; static void ip4_frag_do_fragment (vlib_main_t * vm, u32 pi, u32 ** buffer, ip_frag_error_t * error) { vlib_buffer_t *p; ip4_header_t *ip4; u16 mtu, ptr, len, max, rem, offset, ip_frag_id, ip_frag_offset; u8 *packet, more; vec_add1 (*buffer, pi); p = vlib_get_buffer (vm, pi); offset = vnet_buffer (p)->ip_frag.header_offset; mtu = vnet_buffer (p)->ip_frag.mtu; packet = (u8 *) vlib_buffer_get_current (p); ip4 = (ip4_header_t *) (packet + offset); rem = clib_net_to_host_u16 (ip4->length) - sizeof (*ip4); ptr = 0; max = (mtu - sizeof (*ip4) - vnet_buffer (p)->ip_frag.header_offset) & ~0x7; if (rem < (p->current_length - offset - sizeof (*ip4))) { *error = IP_FRAG_ERROR_MALFORMED; return; } if (mtu < sizeof (*ip4)) { *error = IP_FRAG_ERROR_CANT_FRAGMENT_HEADER; return; } if (ip4->flags_and_fragment_offset & clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT)) { *error = IP_FRAG_ERROR_DONT_FRAGMENT_SET; return; } if (ip4_is_fragment (ip4)) { ip_frag_id = ip4->fragment_id; ip_frag_offset = ip4_get_fragment_offset (ip4); more = ! !(ip4->flags_and_fragment_offset & clib_host_to_net_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS)); } else { ip_frag_id = (++running_fragment_id); ip_frag_offset = 0; more = 0; } //Do the actual fragmentation while (rem) { u32 bi; vlib_buffer_t *b; ip4_header_t *fip4; len = (rem > (mtu - sizeof (*ip4) - vnet_buffer (p)->ip_frag.header_offset)) ? max : rem; if (ptr == 0) { bi = pi; b = p; fip4 = (ip4_header_t *) (vlib_buffer_get_current (b) + offset); } else { if (!vlib_buffer_alloc (vm, &bi, 1)) { *error = IP_FRAG_ERROR_MEMORY; return; } vec_add1 (*buffer, bi); b = vlib_get_buffer (vm, bi); vnet_buffer (b)->sw_if_index[VLIB_RX] = vnet_buffer (p)->sw_if_index[VLIB_RX]; vnet_buffer (b)->sw_if_index[VLIB_TX] = vnet_buffer (p)->sw_if_index[VLIB_TX]; fip4 = (ip4_header_t *) (vlib_buffer_get_current (b) + offset); //Copy offset and ip4 header clib_memcpy (b->data, packet, offset + sizeof (*ip4)); //Copy data clib_memcpy (((u8 *) (fip4)) + sizeof (*fip4), packet + offset + sizeof (*fip4) + ptr, len); } b->current_length = offset + len + sizeof (*fip4); fip4->fragment_id = ip_frag_id; fip4->flags_and_fragment_offset = clib_host_to_net_u16 ((ptr >> 3) + ip_frag_offset); fip4->flags_and_fragment_offset |= clib_host_to_net_u16 (((len != rem) || more) << 13); // ((len0 != rem0) || more0) << 13 is optimization for // ((len0 != rem0) || more0) ? IP4_HEADER_FLAG_MORE_FRAGMENTS : 0 fip4->length = clib_host_to_net_u16 (len + sizeof (*fip4)); fip4->checksum = ip4_header_checksum (fip4); if (vnet_buffer (p)->ip_frag.flags & IP_FRAG_FLAG_IP4_HEADER) { //Encapsulating ipv4 header ip4_header_t *encap_header4 = (ip4_header_t *) vlib_buffer_get_current (b); encap_header4->length = clib_host_to_net_u16 (b->current_length); encap_header4->checksum = ip4_header_checksum (encap_header4); } else if (vnet_buffer (p)->ip_frag.flags & IP_FRAG_FLAG_IP6_HEADER) { //Encapsulating ipv6 header ip6_header_t *encap_header6 = (ip6_header_t *) vlib_buffer_get_current (b); encap_header6->payload_length = clib_host_to_net_u16 (b->current_length - sizeof (*encap_header6)); } rem -= len; ptr += len; } } void ip_frag_set_vnet_buffer (vlib_buffer_t * b, u16 offset, u16 mtu, u8 next_index, u8 flags) { vnet_buffer (b)->ip_frag.header_offset = offset; vnet_buffer (b)->ip_frag.mtu = mtu; vnet_buffer (b)->ip_frag.next_index = next_index; vnet_buffer (b)->ip_frag.flags = flags; } static uword ip4_frag (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame) { u32 n_left_from, *from, next_index, *to_next, n_left_to_next; vlib_node_runtime_t *error_node = vlib_node_get_runtime (vm, ip4_frag_node.index); from = vlib_frame_vector_args (frame); n_left_from = frame->n_vectors; next_index = node->cached_next_index; u32 frag_sent = 0, small_packets = 0; u32 *buffer = 0; while (n_left_from > 0) { vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from > 0 && n_left_to_next > 0) { u32 pi0, *frag_from, frag_left; vlib_buffer_t *p0; ip_frag_error_t error0; ip4_frag_next_t next0; //Note: The packet is not enqueued now. //It is instead put in a vector where other fragments //will be put as well. pi0 = from[0]; from += 1; n_left_from -= 1; error0 = IP_FRAG_ERROR_NONE; p0 = vlib_get_buffer (vm, pi0); ip4_frag_do_fragment (vm, pi0, &buffer, &error0); if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED)) { ip_frag_trace_t *tr = vlib_add_trace (vm, node, p0, sizeof (*tr)); tr->header_offset = vnet_buffer (p0)->ip_frag.header_offset; tr->mtu = vnet_buffer (p0)->ip_frag.mtu; tr->ipv6 = 0; tr->n_fragments = vec_len (buffer); tr->next = vnet_buffer (p0)->ip_frag.next_index; } if (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); vlib_buffer_advance (p0, vnet_buffer (p0)->ip_frag.header_offset); next0 = IP4_FRAG_NEXT_ICMP_ERROR; } else next0 = (error0 == IP_FRAG_ERROR_NONE) ? vnet_buffer (p0)-> ip_frag.next_index : IP4_FRAG_NEXT_DROP; if (error0 == IP_FRAG_ERROR_NONE) { frag_sent += vec_len (buffer); small_packets += (vec_len (buffer) == 1); } else vlib_error_count (vm, ip4_frag_node.index, error0, 1); //Send fragments that were added in the frame frag_from = buffer; frag_left = vec_len (buffer); while (frag_left > 0) { while (frag_left > 0 && n_left_to_next > 0) { u32 i; i = to_next[0] = frag_from[0]; frag_from += 1; frag_left -= 1; to_next += 1; n_left_to_next -= 1; vlib_get_buffer (vm, i)->error = error_node->errors[error0]; vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, i, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); } vec_reset_length (buffer); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } vec_free (buffer); vlib_node_increment_counter (vm, ip4_frag_node.index, IP_FRAG_ERROR_FRAGMENT_SENT, frag_sent); vlib_node_increment_counter (vm, ip4_frag_node.index, IP_FRAG_ERROR_SMALL_PACKET, small_packets); return frame->n_vectors; } static void ip6_frag_do_fragment (vlib_main_t * vm, u32 pi, u32 ** buffer, ip_frag_error_t * error) { vlib_buffer_t *p; ip6_header_t *ip6_hdr; ip6_frag_hdr_t *frag_hdr; u8 *payload, *next_header; p = vlib_get_buffer (vm, pi); //Parsing the IPv6 headers ip6_hdr = vlib_buffer_get_current (p) + vnet_buffer (p)->ip_frag.header_offset; payload = (u8 *) (ip6_hdr + 1); next_header = &ip6_hdr->protocol; if (*next_header == IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS) { next_header = payload; payload += payload[1] * 8; } if (*next_header == IP_PROTOCOL_IP6_DESTINATION_OPTIONS) { next_header = payload; payload += payload[1] * 8; } if (*next_header == IP_PROTOCOL_IPV6_ROUTE) { next_header = payload; payload += payload[1] * 8; } if (PREDICT_FALSE (payload >= (u8 *) vlib_buffer_get_current (p) + p->current_length)) { //A malicious packet could set an extension header with a too big size //and make us modify another vlib_buffer *error = IP_FRAG_ERROR_MALFORMED; return; } u8 has_more; u16 initial_offset; if (*next_header == IP_PROTOCOL_IPV6_FRAGMENTATION) { //The fragmentation header is already there frag_hdr = (ip6_frag_hdr_t *) payload; has_more = ip6_frag_hdr_more (frag_hdr); initial_offset = ip6_frag_hdr_offset (frag_hdr); } else { //Insert a fragmentation header in the packet u8 nh = *next_header; *next_header = IP_PROTOCOL_IPV6_FRAGMENTATION; vlib_buffer_advance (p, -sizeof (*frag_hdr)); u8 *start = vlib_buffer_get_current (p); memmove (start, start + sizeof (*frag_hdr), payload - (start + sizeof (*frag_hdr))); frag_hdr = (ip6_frag_hdr_t *) (payload - sizeof (*frag_hdr)); frag_hdr->identification = ++running_fragment_id; frag_hdr->next_hdr = nh; frag_hdr->rsv = 0; has_more = 0; initial_offset = 0; } payload = (u8 *) (frag_hdr + 1); u16 headers_len = payload - (u8 *) vlib_buffer_get_current (p); u16 max_payload = vnet_buffer (p)->ip_frag.mtu - headers_len; u16 rem = p->current_length - headers_len; u16 ptr = 0; if (max_payload < 8) { *error = IP_FRAG_ERROR_CANT_FRAGMENT_HEADER; return; } while (rem) { u32 bi; vlib_buffer_t *b; u16 len = (rem > max_payload) ? (max_payload & ~0x7) : rem; rem -= len; if (ptr != 0) { if (!vlib_buffer_alloc (vm, &bi, 1)) { *error = IP_FRAG_ERROR_MEMORY; return; } b = vlib_get_buffer (vm, bi); vnet_buffer (b)->sw_if_index[VLIB_RX] = vnet_buffer (p)->sw_if_index[VLIB_RX]; vnet_buffer (b)->sw_if_index[VLIB_TX] = vnet_buffer (p)->sw_if_index[VLIB_TX]; clib_memcpy (vlib_buffer_get_current (b), vlib_buffer_get_current (p), headers_len); clib_memcpy (vlib_buffer_get_current (b) + headers_len, payload + ptr, len); frag_hdr = vlib_buffer_get_current (b) + headers_len - sizeof (*frag_hdr); } else { bi = pi; b = vlib_get_buffer (vm, bi); //frag_hdr already set here } ip6_hdr = vlib_buffer_get_current (b) + vnet_buffer (p)->ip_frag.header_offset; frag_hdr->fragment_offset_and_more = ip6_frag_hdr_offset_and_more (initial_offset + (ptr >> 3), (rem || has_more)); b->current_length = headers_len + len; ip6_hdr->payload_length = clib_host_to_net_u16 (b->current_length - vnet_buffer (p)->ip_frag.header_offset - sizeof (*ip6_hdr)); if (vnet_buffer (p)->ip_frag.flags & IP_FRAG_FLAG_IP4_HEADER) { //Encapsulating ipv4 header ip4_header_t *encap_header4 = (ip4_header_t *) vlib_buffer_get_current (b); encap_header4->length = clib_host_to_net_u16 (b->current_length); encap_header4->checksum = ip4_header_checksum (encap_header4); } else if (vnet_buffer (p)->ip_frag.flags & IP_FRAG_FLAG_IP6_HEADER) { //Encapsulating ipv6 header ip6_header_t *encap_header6 = (ip6_header_t *) vlib_buffer_get_current (b); encap_header6->payload_length = clib_host_to_net_u16 (b->current_length - sizeof (*encap_header6)); } vec_add1 (*buffer, bi); ptr += len; } } static uword ip6_frag (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame) { u32 n_left_from, *from, next_index, *to_next, n_left_to_next; vlib_node_runtime_t *error_node = vlib_node_get_runtime (vm, ip6_frag_node.index); from = vlib_frame_vector_args (frame); n_left_from = frame->n_vectors; next_index = node->cached_next_index; u32 frag_sent = 0, small_packets = 0; u32 *buffer = 0; while (n_left_from > 0) { vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from > 0 && n_left_to_next > 0) { u32 pi0, *frag_from, frag_left; vlib_buffer_t *p0; ip_frag_error_t error0; ip6_frag_next_t next0; pi0 = from[0]; from += 1; n_left_from -= 1; error0 = IP_FRAG_ERROR_NONE; p0 = vlib_get_buffer (vm, pi0); ip6_frag_do_fragment (vm, pi0, &buffer, &error0); if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED)) { ip_frag_trace_t *tr = vlib_add_trace (vm, node, p0, sizeof (*tr)); tr->header_offset = vnet_buffer (p0)->ip_frag.header_offset; tr->mtu = vnet_buffer (p0)->ip_frag.mtu; tr->ipv6 = 1; tr->n_fragments = vec_len (buffer); tr->next = vnet_buffer (p0)->ip_frag.next_index; } next0 = (error0 == IP_FRAG_ERROR_NONE) ? vnet_buffer (p0)-> ip_frag.next_index : IP6_FRAG_NEXT_DROP; frag_sent += vec_len (buffer); small_packets += (vec_len (buffer) == 1); //Send fragments that were added in the frame frag_from = buffer; frag_left = vec_len (buffer); while (frag_left > 0) { while (frag_left > 0 && n_left_to_next > 0) { u32 i; i = to_next[0] = frag_from[0]; frag_from += 1; frag_left -= 1; to_next += 1; n_left_to_next -= 1; vlib_get_buffer (vm, i)->error = error_node->errors[error0]; vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, i, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); } vec_reset_length (buffer); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } vec_free (buffer); vlib_node_increment_counter (vm, ip6_frag_node.index, IP_FRAG_ERROR_FRAGMENT_SENT, frag_sent); vlib_node_increment_counter (vm, ip6_frag_node.index, IP_FRAG_ERROR_SMALL_PACKET, small_packets); return frame->n_vectors; } static char *ip4_frag_error_strings[] = { #define _(sym,string) string, foreach_ip_frag_error #undef _ }; /* *INDENT-OFF* */ VLIB_REGISTER_NODE (ip4_frag_node) = { .function = ip4_frag, .name = IP4_FRAG_NODE_NAME, .vector_size = sizeof (u32), .format_trace = format_ip_frag_trace, .type = VLIB_NODE_TYPE_INTERNAL, .n_errors = IP_FRAG_N_ERROR, .error_strings = ip4_frag_error_strings, .n_next_nodes = IP4_FRAG_N_NEXT, .next_nodes = { [IP4_FRAG_NEXT_IP4_LOOKUP] = "ip4-lookup", [IP4_FRAG_NEXT_IP6_LOOKUP] = "ip6-lookup", [IP4_FRAG_NEXT_ICMP_ERROR] = "ip4-icmp-error", [IP4_FRAG_NEXT_DROP] = "error-drop" }, }; /* *INDENT-ON* */ /* *INDENT-OFF* */ VLIB_REGISTER_NODE (ip6_frag_node) = { .function = ip6_frag, .name = IP6_FRAG_NODE_NAME, .vector_size = sizeof (u32), .format_trace = format_ip_frag_trace, .type = VLIB_NODE_TYPE_INTERNAL, .n_errors = IP_FRAG_N_ERROR, .error_strings = ip4_frag_error_strings, .n_next_nodes = IP6_FRAG_N_NEXT, .next_nodes = { [IP6_FRAG_NEXT_IP4_LOOKUP] = "ip4-lookup", [IP6_FRAG_NEXT_IP6_LOOKUP] = "ip6-lookup", [IP6_FRAG_NEXT_DROP] = "error-drop" }, }; /* *INDENT-ON* */ /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */