diff options
Diffstat (limited to 'test/packetdrill/checksum.c')
-rw-r--r-- | test/packetdrill/checksum.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/test/packetdrill/checksum.c b/test/packetdrill/checksum.c new file mode 100644 index 0000000..3e549d3 --- /dev/null +++ b/test/packetdrill/checksum.c @@ -0,0 +1,239 @@ +/* + * Copyright 2013 Google Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ +/* + * Author: ncardwell@google.com (Neal Cardwell) + * + * Helpers to calculate IP, TCP, and UDP checksums. + */ + +#include "checksum.h" + +#include "assert.h" + +/* Add bytes in buffer to a running checksum. Returns the new + * intermediate checksum. Use ip_checksum_fold() to convert the + * intermediate checksum to final form. + */ +static u64 ip_checksum_partial(const void *p, size_t len, u64 sum) +{ + /* Main loop: 32 bits at a time. + * We take advantage of intel's ability to do unaligned memory + * accesses with minimal additional cost. Other architectures + * probably want to be more careful here. + */ + const u32 *p32 = (const u32 *)(p); + for (; len >= sizeof(*p32); len -= sizeof(*p32)) + sum += *p32++; + + /* Handle un-32bit-aligned trailing bytes */ + const u16 *p16 = (const u16 *)(p32); + if (len >= 2) { + sum += *p16++; + len -= sizeof(*p16); + } + if (len > 0) { + const u8 *p8 = (const u8 *)(p16); + sum += ntohs(*p8 << 8); /* RFC says pad last byte */ + } + + return sum; +} + +static __be16 ip_checksum_fold(u64 sum) +{ + while (sum & ~0xffffffffULL) + sum = (sum >> 32) + (sum & 0xffffffffULL); + while (sum & 0xffff0000ULL) + sum = (sum >> 16) + (sum & 0xffffULL); + + return ~sum; +} + +static u64 tcp_udp_v4_header_checksum_partial( + struct in_addr src_ip, struct in_addr dst_ip, u8 protocol, u16 len) +{ + /* The IPv4 pseudo-header is defined in RFC 793, Section 3.1. */ + struct ipv4_pseudo_header_t { + /* We use a union here to avoid aliasing issues with gcc -O2 */ + union { + struct header { + struct in_addr src_ip; + struct in_addr dst_ip; + __u8 mbz; + __u8 protocol; + __be16 length; + } __packed fields; + u32 words[3]; + }; + }; + struct ipv4_pseudo_header_t pseudo_header; + assert(sizeof(pseudo_header) == 12); + + /* Fill in the pseudo-header. */ + pseudo_header.fields.src_ip = src_ip; + pseudo_header.fields.dst_ip = dst_ip; + pseudo_header.fields.mbz = 0; + pseudo_header.fields.protocol = protocol; + pseudo_header.fields.length = htons(len); + return ip_checksum_partial(&pseudo_header, sizeof(pseudo_header), 0); +} + +__be16 tcp_udp_v4_checksum(struct in_addr src_ip, struct in_addr dst_ip, + u8 protocol, const void *payload, u16 len) +{ + u64 sum = tcp_udp_v4_header_checksum_partial( + src_ip, dst_ip, protocol, len); + sum = ip_checksum_partial(payload, len, sum); + return ip_checksum_fold(sum); +} + +/* Calculates and returns IPv4 header checksum. */ +__be16 ipv4_checksum(void *ip_header, size_t ip_header_bytes) +{ + return ip_checksum_fold( + ip_checksum_partial(ip_header, ip_header_bytes, 0)); +} + +static u64 tcp_udp_v6_header_checksum_partial( + const struct in6_addr *src_ip, + const struct in6_addr *dst_ip, + u8 protocol, u32 len) +{ + /* The IPv6 pseudo-header is defined in RFC 2460, Section 8.1. */ + struct ipv6_pseudo_header_t { + /* We use a union here to avoid aliasing issues with gcc -O2 */ + union { + struct header { + struct in6_addr src_ip; + struct in6_addr dst_ip; + __be32 length; + __u8 mbz[3]; + __u8 next_header; + } __packed fields; + u32 words[10]; + }; + }; + struct ipv6_pseudo_header_t pseudo_header; + assert(sizeof(pseudo_header) == 40); + + /* Fill in the pseudo-header. */ + pseudo_header.fields.src_ip = *src_ip; + pseudo_header.fields.dst_ip = *dst_ip; + pseudo_header.fields.length = htonl(len); + memset(pseudo_header.fields.mbz, 0, sizeof(pseudo_header.fields.mbz)); + pseudo_header.fields.next_header = protocol; + return ip_checksum_partial(&pseudo_header, sizeof(pseudo_header), 0); +} + +__be16 tcp_udp_v6_checksum(const struct in6_addr *src_ip, + const struct in6_addr *dst_ip, + u8 protocol, const void *payload, u32 len) +{ + u64 sum = tcp_udp_v6_header_checksum_partial( + src_ip, dst_ip, protocol, len); + sum = ip_checksum_partial(payload, len, sum); + return ip_checksum_fold(sum); +} + +#define CRC32C(c, d) (c = (c>>8) ^ crc_c[(c^(d))&0xFF]) + +static u32 crc_c[256] = { + 0x00000000, 0xF26B8303, 0xE13B70F7, 0x1350F3F4, + 0xC79A971F, 0x35F1141C, 0x26A1E7E8, 0xD4CA64EB, + 0x8AD958CF, 0x78B2DBCC, 0x6BE22838, 0x9989AB3B, + 0x4D43CFD0, 0xBF284CD3, 0xAC78BF27, 0x5E133C24, + 0x105EC76F, 0xE235446C, 0xF165B798, 0x030E349B, + 0xD7C45070, 0x25AFD373, 0x36FF2087, 0xC494A384, + 0x9A879FA0, 0x68EC1CA3, 0x7BBCEF57, 0x89D76C54, + 0x5D1D08BF, 0xAF768BBC, 0xBC267848, 0x4E4DFB4B, + 0x20BD8EDE, 0xD2D60DDD, 0xC186FE29, 0x33ED7D2A, + 0xE72719C1, 0x154C9AC2, 0x061C6936, 0xF477EA35, + 0xAA64D611, 0x580F5512, 0x4B5FA6E6, 0xB93425E5, + 0x6DFE410E, 0x9F95C20D, 0x8CC531F9, 0x7EAEB2FA, + 0x30E349B1, 0xC288CAB2, 0xD1D83946, 0x23B3BA45, + 0xF779DEAE, 0x05125DAD, 0x1642AE59, 0xE4292D5A, + 0xBA3A117E, 0x4851927D, 0x5B016189, 0xA96AE28A, + 0x7DA08661, 0x8FCB0562, 0x9C9BF696, 0x6EF07595, + 0x417B1DBC, 0xB3109EBF, 0xA0406D4B, 0x522BEE48, + 0x86E18AA3, 0x748A09A0, 0x67DAFA54, 0x95B17957, + 0xCBA24573, 0x39C9C670, 0x2A993584, 0xD8F2B687, + 0x0C38D26C, 0xFE53516F, 0xED03A29B, 0x1F682198, + 0x5125DAD3, 0xA34E59D0, 0xB01EAA24, 0x42752927, + 0x96BF4DCC, 0x64D4CECF, 0x77843D3B, 0x85EFBE38, + 0xDBFC821C, 0x2997011F, 0x3AC7F2EB, 0xC8AC71E8, + 0x1C661503, 0xEE0D9600, 0xFD5D65F4, 0x0F36E6F7, + 0x61C69362, 0x93AD1061, 0x80FDE395, 0x72966096, + 0xA65C047D, 0x5437877E, 0x4767748A, 0xB50CF789, + 0xEB1FCBAD, 0x197448AE, 0x0A24BB5A, 0xF84F3859, + 0x2C855CB2, 0xDEEEDFB1, 0xCDBE2C45, 0x3FD5AF46, + 0x7198540D, 0x83F3D70E, 0x90A324FA, 0x62C8A7F9, + 0xB602C312, 0x44694011, 0x5739B3E5, 0xA55230E6, + 0xFB410CC2, 0x092A8FC1, 0x1A7A7C35, 0xE811FF36, + 0x3CDB9BDD, 0xCEB018DE, 0xDDE0EB2A, 0x2F8B6829, + 0x82F63B78, 0x709DB87B, 0x63CD4B8F, 0x91A6C88C, + 0x456CAC67, 0xB7072F64, 0xA457DC90, 0x563C5F93, + 0x082F63B7, 0xFA44E0B4, 0xE9141340, 0x1B7F9043, + 0xCFB5F4A8, 0x3DDE77AB, 0x2E8E845F, 0xDCE5075C, + 0x92A8FC17, 0x60C37F14, 0x73938CE0, 0x81F80FE3, + 0x55326B08, 0xA759E80B, 0xB4091BFF, 0x466298FC, + 0x1871A4D8, 0xEA1A27DB, 0xF94AD42F, 0x0B21572C, + 0xDFEB33C7, 0x2D80B0C4, 0x3ED04330, 0xCCBBC033, + 0xA24BB5A6, 0x502036A5, 0x4370C551, 0xB11B4652, + 0x65D122B9, 0x97BAA1BA, 0x84EA524E, 0x7681D14D, + 0x2892ED69, 0xDAF96E6A, 0xC9A99D9E, 0x3BC21E9D, + 0xEF087A76, 0x1D63F975, 0x0E330A81, 0xFC588982, + 0xB21572C9, 0x407EF1CA, 0x532E023E, 0xA145813D, + 0x758FE5D6, 0x87E466D5, 0x94B49521, 0x66DF1622, + 0x38CC2A06, 0xCAA7A905, 0xD9F75AF1, 0x2B9CD9F2, + 0xFF56BD19, 0x0D3D3E1A, 0x1E6DCDEE, 0xEC064EED, + 0xC38D26C4, 0x31E6A5C7, 0x22B65633, 0xD0DDD530, + 0x0417B1DB, 0xF67C32D8, 0xE52CC12C, 0x1747422F, + 0x49547E0B, 0xBB3FFD08, 0xA86F0EFC, 0x5A048DFF, + 0x8ECEE914, 0x7CA56A17, 0x6FF599E3, 0x9D9E1AE0, + 0xD3D3E1AB, 0x21B862A8, 0x32E8915C, 0xC083125F, + 0x144976B4, 0xE622F5B7, 0xF5720643, 0x07198540, + 0x590AB964, 0xAB613A67, 0xB831C993, 0x4A5A4A90, + 0x9E902E7B, 0x6CFBAD78, 0x7FAB5E8C, 0x8DC0DD8F, + 0xE330A81A, 0x115B2B19, 0x020BD8ED, 0xF0605BEE, + 0x24AA3F05, 0xD6C1BC06, 0xC5914FF2, 0x37FACCF1, + 0x69E9F0D5, 0x9B8273D6, 0x88D28022, 0x7AB90321, + 0xAE7367CA, 0x5C18E4C9, 0x4F48173D, 0xBD23943E, + 0xF36E6F75, 0x0105EC76, 0x12551F82, 0xE03E9C81, + 0x34F4F86A, 0xC69F7B69, 0xD5CF889D, 0x27A40B9E, + 0x79B737BA, 0x8BDCB4B9, 0x988C474D, 0x6AE7C44E, + 0xBE2DA0A5, 0x4C4623A6, 0x5F16D052, 0xAD7D5351 +}; + +__be32 sctp_crc32c(const void *packet, u32 len) +{ + u32 i, crc32c; + u8 byte0, byte1, byte2, byte3; + const u8 *buf = (const u8 *)packet; + + crc32c = ~0; + for (i = 0; i < len; i++) + CRC32C(crc32c, buf[i]); + crc32c = ~crc32c; + byte0 = crc32c & 0xff; + byte1 = (crc32c>>8) & 0xff; + byte2 = (crc32c>>16) & 0xff; + byte3 = (crc32c>>24) & 0xff; + crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3); + return htonl(crc32c); +} |