diff options
Diffstat (limited to 'ipv4.c')
| -rw-r--r-- | ipv4.c | 146 |
1 files changed, 0 insertions, 146 deletions
@@ -1,146 +0,0 @@ -/* - * Copyright 2011 Daniel Drown - * - * 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.c - takes ipv4 packets, finds their headers, and then calls translation functions on them - */ -#include <string.h> - -#include "checksum.h" -#include "debug.h" -#include "dump.h" -#include "logging.h" -#include "translate.h" - -/* function: icmp_packet - * translates an icmp packet - * out - output packet - * icmp - pointer to icmp header in packet - * checksum - pseudo-header checksum - * len - size of ip payload - * returns: the highest position in the output clat_packet that's filled in - */ -int icmp_packet(clat_packet out, clat_packet_index pos, const struct icmphdr *icmp, - uint32_t checksum, size_t len) { - const uint8_t *payload; - size_t payload_size; - - if (len < sizeof(struct icmphdr)) { - logmsg_dbg(ANDROID_LOG_ERROR, "icmp_packet/(too small)"); - return 0; - } - - payload = (const uint8_t *)(icmp + 1); - payload_size = len - sizeof(struct icmphdr); - - return icmp_to_icmp6(out, pos, icmp, checksum, payload, payload_size); -} - -/* function: ipv4_packet - * translates an ipv4 packet - * out - output packet - * packet - packet data - * len - size of packet - * returns: the highest position in the output clat_packet that's filled in - */ -int ipv4_packet(clat_packet out, clat_packet_index pos, const uint8_t *packet, size_t len) { - const struct iphdr *header = (struct iphdr *)packet; - struct ip6_hdr *ip6_targ = (struct ip6_hdr *)out[pos].iov_base; - struct ip6_frag *frag_hdr; - size_t frag_hdr_len; - uint8_t nxthdr; - const uint8_t *next_header; - size_t len_left; - uint32_t old_sum, new_sum; - int iov_len; - - if (len < sizeof(struct iphdr)) { - logmsg_dbg(ANDROID_LOG_ERROR, "ip_packet/too short for an ip header"); - return 0; - } - - if (header->ihl < 5) { - logmsg_dbg(ANDROID_LOG_ERROR, "ip_packet/ip header length set to less than 5: %x", header->ihl); - return 0; - } - - if ((size_t)header->ihl * 4 > len) { // ip header length larger than entire packet - logmsg_dbg(ANDROID_LOG_ERROR, "ip_packet/ip header length set too large: %x", header->ihl); - return 0; - } - - if (header->version != 4) { - logmsg_dbg(ANDROID_LOG_ERROR, "ip_packet/ip header version not 4: %x", header->version); - return 0; - } - - /* rfc6145 - If any IPv4 options are present in the IPv4 packet, they MUST be - * ignored and the packet translated normally; there is no attempt to - * translate the options. - */ - - next_header = packet + header->ihl * 4; - len_left = len - header->ihl * 4; - - nxthdr = header->protocol; - if (nxthdr == IPPROTO_ICMP) { - // ICMP and ICMPv6 have different protocol numbers. - nxthdr = IPPROTO_ICMPV6; - } - - /* Fill in the IPv6 header. We need to do this before we translate the packet because TCP and - * UDP include parts of the IP header in the checksum. Set the length to zero because we don't - * know it yet. - */ - fill_ip6_header(ip6_targ, 0, nxthdr, header); - out[pos].iov_len = sizeof(struct ip6_hdr); - - /* Calculate the pseudo-header checksum. - * Technically, the length that is used in the pseudo-header checksum is the transport layer - * length, which is not the same as len_left in the case of fragmented packets. But since - * translation does not change the transport layer length, the checksum is unaffected. - */ - old_sum = ipv4_pseudo_header_checksum(header, len_left); - new_sum = ipv6_pseudo_header_checksum(ip6_targ, len_left, nxthdr); - - // If the IPv4 packet is fragmented, add a Fragment header. - frag_hdr = (struct ip6_frag *)out[pos + 1].iov_base; - frag_hdr_len = maybe_fill_frag_header(frag_hdr, ip6_targ, header); - out[pos + 1].iov_len = frag_hdr_len; - - if (frag_hdr_len && frag_hdr->ip6f_offlg & IP6F_OFF_MASK) { - // Non-first fragment. Copy the rest of the packet as is. - iov_len = generic_packet(out, pos + 2, next_header, len_left); - } else if (nxthdr == IPPROTO_ICMPV6) { - iov_len = icmp_packet(out, pos + 2, (const struct icmphdr *)next_header, new_sum, len_left); - } else if (nxthdr == IPPROTO_TCP) { - iov_len = - tcp_packet(out, pos + 2, (const struct tcphdr *)next_header, old_sum, new_sum, len_left); - } else if (nxthdr == IPPROTO_UDP) { - iov_len = - udp_packet(out, pos + 2, (const struct udphdr *)next_header, old_sum, new_sum, len_left); - } else if (nxthdr == IPPROTO_GRE || nxthdr == IPPROTO_ESP) { - iov_len = generic_packet(out, pos + 2, next_header, len_left); - } else { -#if CLAT_DEBUG - logmsg_dbg(ANDROID_LOG_ERROR, "ip_packet/unknown protocol: %x", header->protocol); - logcat_hexdump("ipv4/protocol", packet, len); -#endif - return 0; - } - - // Set the length. - ip6_targ->ip6_plen = htons(packet_length(out, pos)); - return iov_len; -} |