/*--------------------------------------------------------------------------- * 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 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 mtu: %u fragments: %u", t->ipv6 ? "6" : "4", t->mtu, t->n_fragments); return s; } static u32 running_fragment_id; static void frag_set_sw_if_index (vlib_buffer_t * to, vlib_buffer_t * from) { vnet_buffer (to)->sw_if_index[VLIB_RX] = vnet_buffer (from)->sw_if_index[VLIB_RX]; vnet_buffer (to)->sw_if_index[VLIB_TX] = vnet_buffer (from)->sw_if_index[VLIB_TX]; /* Copy adj_index in case DPO based node is sending for the * fragmentation, the packet would be sent back to the proper * DPO next node and Index */ vnet_buffer (to)->ip.adj_index[VLIB_RX] = vnet_buffer (from)->ip.adj_index[VLIB_RX]; vnet_buffer (to)->ip.adj_index[VLIB_TX] = vnet_buffer (from)->ip.adj_index[VLIB_TX]; /* Copy QoS Bits */ if (PREDICT_TRUE (from->flags & VNET_BUFFER_F_QOS_DATA_VALID)) { vnet_buffer2 (to)->qos = vnet_buffer2 (from)->qos; to->flags |= VNET_BUFFER_F_QOS_DATA_VALID; } } static vlib_buffer_t * frag_buffer_alloc (vlib_buffer_t * org_b, u32 * bi) { vlib_main_t *vm = vlib_get_main (); if (vlib_buffer_alloc (vm, bi, 1) != 1) return 0; vlib_buffer_t *b = vlib_get_buffer (vm, *bi); VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b); vlib_buffer_copy_trace_flag (vm, org_b, *bi); return b; } /* * Limitation: Does follow buffer chains in the packet to fragment, * but does not generate buffer chains. I.e. a fragment is always * contained with in a single buffer and limited to the max buffer * size. */ void ip4_frag_do_fragment (vlib_main_t * vm, u32 from_bi, u32 ** buffer, ip_frag_error_t * error) { vlib_buffer_t *from_b; ip4_header_t *ip4; u16 mtu, len, max, rem, ip_frag_id, ip_frag_offset; u8 *org_from_packet, more; from_b = vlib_get_buffer (vm, from_bi); mtu = vnet_buffer (from_b)->ip_frag.mtu; org_from_packet = vlib_buffer_get_current (from_b); ip4 = (ip4_header_t *) vlib_buffer_get_current (from_b); rem = clib_net_to_host_u16 (ip4->length) - sizeof (ip4_header_t); max = (clib_min (mtu, vlib_buffer_get_default_data_size (vm)) - sizeof (ip4_header_t)) & ~0x7; if (rem > (vlib_buffer_length_in_chain (vm, from_b) - sizeof (ip4_header_t))) { *error = IP_FRAG_ERROR_MALFORMED; return; } if (mtu < sizeof (ip4_header_t)) { *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; } u8 *from_data = (void *) (ip4 + 1); vlib_buffer_t *org_from_b = from_b; u16 fo = 0; u16 left_in_from_buffer = from_b->current_length - sizeof (ip4_header_t); u16 ptr = 0; /* Do the actual fragmentation */ while (rem) { u32 to_bi; vlib_buffer_t *to_b; ip4_header_t *to_ip4; u8 *to_data; 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) { *error = IP_FRAG_ERROR_MEMORY; return; } vec_add1 (*buffer, to_bi); frag_set_sw_if_index (to_b, org_from_b); /* Copy ip4 header */ clib_memcpy_fast (to_b->data, org_from_packet, sizeof (ip4_header_t)); to_ip4 = vlib_buffer_get_current (to_b); to_data = (void *) (to_ip4 + 1); /* Spin through from buffers filling up the to buffer */ u16 left_in_to_buffer = len, to_ptr = 0; while (1) { u16 bytes_to_copy; /* Figure out how many bytes we can safely copy */ bytes_to_copy = left_in_to_buffer <= left_in_from_buffer ? left_in_to_buffer : left_in_from_buffer; clib_memcpy_fast (to_data + to_ptr, from_data + ptr, bytes_to_copy); left_in_to_buffer -= bytes_to_copy; ptr += bytes_to_copy; left_in_from_buffer -= bytes_to_copy; if (left_in_to_buffer == 0) break; ASSERT (left_in_from_buffer <= 0); /* Move buffer */ if (!(from_b->flags & VLIB_BUFFER_NEXT_PRESENT)) { *error = IP_FRAG_ERROR_MALFORMED; return; } from_b = vlib_get_buffer (vm, from_b->next_buffer); from_data = (u8 *) vlib_buffer_get_current (from_b); ptr = 0; left_in_from_buffer = from_b->current_length; to_ptr += bytes_to_copy; } to_b->current_length = len + sizeof (ip4_header_t); to_ip4->fragment_id = ip_frag_id; to_ip4->flags_and_fragment_offset = clib_host_to_net_u16 ((fo >> 3) + ip_frag_offset); to_ip4->flags_and_fragment_offset |= clib_host_to_net_u16 (((len != rem) || more) << 13); to_ip4->length = clib_host_to_net_u16 (len + sizeof (ip4_header_t)); to_ip4->checksum = ip4_header_checksum (to_ip4); if (vnet_buffer (org_from_b)->ip_frag.flags & IP_FRAG_FLAG_IP4_HEADER) { /* Encapsulating ipv4 header */ ip4_header_t *encap_header4 = (ip4_header_t *) vlib_buffer_get_current (to_b); encap_header4->length = clib_host_to_net_u16 (to_b->current_length); encap_header4->checksum = ip4_header_checksum (encap_header4); } else if (vnet_buffer (org_from_b)-> ip_frag.flags & IP_FRAG_FLAG_IP6_HEADER) { /* Encapsulating ipv6 header */ ip6_header_t *encap_header6 = (ip6_header_t *) vlib_buffer_get_current (to_b); encap_header6->payload_length = clib_host_to_net_u16 (to_b->current_length - sizeof (*encap_header6)); } rem -= len; fo += len; } } void ip_frag_set_vnet_buffer (vlib_buffer_t * b, u16 mtu, u8 next_index, u8 flags) { vnet_buffer (b)->ip_frag.mtu = mtu; vnet_buffer (b)->ip_frag.next_index = next_index; vnet_buffer (b)->ip_frag.flags = flags; } static inline uword frag_node_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame, u32 node_index, bool is_ip6) { u32 n_left_from, *from, next_index, *to_next, n_left_to_next; vlib_node_runtime_t *error_node = vlib_node_get_runtime (vm, 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; int 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); if (is_ip6) ip6_frag_do_fragment (vm, pi0, &buffer, &error0); else 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->mtu = vnet_buffer (p0)->ip_frag.mtu; tr->ipv6 = is_ip6 ? 1 : 0; tr->n_fragments = vec_len (buffer); tr->next = vnet_buffer (p0)->ip_frag.next_index; } if (!is_ip6 && 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 = IP4_FRAG_NEXT_ICMP_ERROR; } else { if (is_ip6) next0 = (error0 == IP_FRAG_ERROR_NONE) ? vnet_buffer (p0)-> ip_frag.next_index : IP6_FRAG_NEXT_DROP; else next0 = (error0 == IP_FRAG_ERROR_NONE) ? vnet_buffer (p0)-> ip_frag.next_index : IP4_FRAG_NEXT_DROP; } if (error0 == IP_FRAG_ERROR_NONE) { /* Free original buffer chain */ frag_sent += vec_len (buffer); small_packets += (vec_len (buffer) == 1); vlib_buffer_free_one (vm, pi0); /* Free original packet */ } else { vlib_error_count (vm, node_index, error0, 1); vec_add1 (buffer, pi0); /* Get rid of the original buffer */ } /* 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, node_index, IP_FRAG_ERROR_FRAGMENT_SENT, frag_sent); vlib_node_increment_counter (vm, node_index, IP_FRAG_ERROR_SMALL_PACKET, small_packets); return frame->n_vectors; } static uword ip4_frag (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame) { return frag_node_inline (vm, node, frame, ip4_frag_node.index, 0 /* is_ip6 */ ); } static uword ip6_frag (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame) { return frag_node_inline (vm, node, frame, ip6_frag_node.index, 1 /* is_ip6 */ ); } /* * Fragments the packet given in from_bi. Fragments are returned in the buffer vector. * Caller must ensure the original packet is freed. */ void ip6_frag_do_fragment (vlib_main_t * vm, u32 from_bi, u32 ** buffer, ip_frag_error_t * error) { vlib_buffer_t *from_b; ip6_header_t *ip6; u16 mtu, len, max, rem, ip_frag_id; from_b = vlib_get_buffer (vm, from_bi); mtu = vnet_buffer (from_b)->ip_frag.mtu; ip6 = (ip6_header_t *) vlib_buffer_get_current (from_b); 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?? if (rem > (vlib_buffer_length_in_chain (vm, from_b) - sizeof (ip6_header_t))) { *error = IP_FRAG_ERROR_MALFORMED; return; } /* TODO: Look through header chain for fragmentation header */ if (ip6->protocol == IP_PROTOCOL_IPV6_FRAGMENTATION) { *error = IP_FRAG_ERROR_MALFORMED; return; } u8 *from_data = (void *) (ip6 + 1); vlib_buffer_t *org_from_b = from_b; u16 fo = 0; u16 left_in_from_buffer = from_b->current_length - sizeof (ip6_header_t); u16 ptr = 0; ip_frag_id = ++running_fragment_id; // Fix /* Do the actual fragmentation */ while (rem) { u32 to_bi; vlib_buffer_t *to_b; ip6_header_t *to_ip6; ip6_frag_hdr_t *to_frag_hdr; u8 *to_data; len = (rem > (mtu - sizeof (ip6_header_t) - sizeof (ip6_frag_hdr_t)) ? 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) { *error = IP_FRAG_ERROR_MEMORY; return; } vec_add1 (*buffer, to_bi); frag_set_sw_if_index (to_b, org_from_b); /* Copy ip6 header */ clib_memcpy_fast (to_b->data, ip6, sizeof (ip6_header_t)); to_ip6 = vlib_buffer_get_current (to_b); to_frag_hdr = (ip6_frag_hdr_t *) (to_ip6 + 1); to_data = (void *) (to_frag_hdr + 1); /* Spin through from buffers filling up the to buffer */ u16 left_in_to_buffer = len, to_ptr = 0; while (1) { u16 bytes_to_copy; /* Figure out how many bytes we can safely copy */ bytes_to_copy = left_in_to_buffer <= left_in_from_buffer ? left_in_to_buffer : left_in_from_buffer; clib_memcpy_fast (to_data + to_ptr, from_data + ptr, bytes_to_copy); left_in_to_buffer -= bytes_to_copy; ptr += bytes_to_copy; left_in_from_buffer -= bytes_to_copy; if (left_in_to_buffer == 0) break; ASSERT (left_in_from_buffer <= 0); /* Move buffer */ if (!(from_b->flags & VLIB_BUFFER_NEXT_PRESENT)) { *error = IP_FRAG_ERROR_MALFORMED; return; } from_b = vlib_get_buffer (vm, from_b->next_buffer); from_data = (u8 *) vlib_buffer_get_current (from_b); ptr = 0; left_in_from_buffer = from_b->current_length; to_ptr += bytes_to_copy; } to_b->current_length = len + sizeof (ip6_header_t) + sizeof (ip6_frag_hdr_t); to_ip6->payload_length = clib_host_to_net_u16 (len + sizeof (ip6_frag_hdr_t)); to_ip6->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION; to_frag_hdr->fragment_offset_and_more = ip6_frag_hdr_offset_and_more ((fo >> 3), len != rem); to_frag_hdr->identification = ip_frag_id; to_frag_hdr->next_hdr = ip6->protocol; to_frag_hdr->rsv = 0; rem -= len; fo += len; } } 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_REWRITE] = "ip4-rewrite", [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] = "ip4-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_IP6_REWRITE] = "ip6-rewrite", [IP6_FRAG_NEXT_IP4_LOOKUP] = "ip4-lookup", [IP6_FRAG_NEXT_IP6_LOOKUP] = "ip6-lookup", [IP6_FRAG_NEXT_DROP] = "ip6-drop" }, }; /* *INDENT-ON* */ /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */