Index: uspace/lib/net/generic/net_checksum.c =================================================================== --- uspace/lib/net/generic/net_checksum.c (revision b01f8788bb8fbbd617e4a54a67918bcf51f14239) +++ uspace/lib/net/generic/net_checksum.c (revision 8d601dbff714a8e33d29f4c80051a46e4121abb4) @@ -27,10 +27,10 @@ */ -/** @addtogroup net - * @{ +/** @addtogroup libnet + * @{ */ /** @file - * General CRC and checksum computation implementation. + * General CRC and checksum computation implementation. */ @@ -39,71 +39,93 @@ #include -/** Big-endian encoding CRC divider. - */ -#define CRC_DIVIDER_BE 0x04C11DB7 - -/** Little-endian encoding CRC divider. - */ -#define CRC_DIVIDER_LE 0xEDB88320 - -uint16_t compact_checksum(uint32_t sum){ +/** Big-endian encoding CRC divider. */ +#define CRC_DIVIDER_BE 0x04c11db7 + +/** Little-endian encoding CRC divider. */ +#define CRC_DIVIDER_LE 0xedb88320 + +/** Compacts the computed checksum to the 16 bit number adding the carries. + * + * @param[in] sum Computed checksum. + * @returns Compacted computed checksum to the 16 bits. + */ +uint16_t compact_checksum(uint32_t sum) +{ // shorten to the 16 bits - while(sum >> 16){ - sum = (sum &0xFFFF) + (sum >> 16); - } + while (sum >> 16) + sum = (sum & 0xffff) + (sum >> 16); return (uint16_t) sum; } -uint32_t compute_checksum(uint32_t seed, uint8_t * data, size_t length){ +/** Computes sum of the 2 byte fields. + * + * Padds one zero (0) byte if odd. + * + * @param[in] seed Initial value. Often used as 0 or ~0. + * @param[in] data Pointer to the beginning of data to process. + * @param[in] length Length of the data in bytes. + * @returns The computed checksum of the length bytes of the data. + */ +uint32_t compute_checksum(uint32_t seed, uint8_t *data, size_t length) +{ size_t index; // sum all the 16 bit fields - for(index = 0; index + 1 < length; index += 2){ + for (index = 0; index + 1 < length; index += 2) seed += (data[index] << 8) + data[index + 1]; - } // last odd byte with zero padding - if(index + 1 == length){ + if (index + 1 == length) seed += data[index] << 8; - } return seed; } -uint32_t compute_crc32_be(uint32_t seed, uint8_t * data, size_t length){ +/** Computes CRC32 value in the big-endian environment. + * + * @param[in] seed Initial value. Often used as 0 or ~0. + * @param[in] data Pointer to the beginning of data to process. + * @param[in] length Length of the data in bits. + * @returns The computed CRC32 of the length bits of the data. + */ +uint32_t compute_crc32_be(uint32_t seed, uint8_t * data, size_t length) +{ size_t index; // process full bytes - while(length >= 8){ + while (length >= 8) { // add the data seed ^= (*data) << 24; + // for each added bit - for(index = 0; index < 8; ++ index){ + for (index = 0; index < 8; ++index) { // if the first bit is set - if(seed &0x80000000){ + if (seed & 0x80000000) { // shift and divide the checksum seed = (seed << 1) ^ ((uint32_t) CRC_DIVIDER_BE); - }else{ + } else { // shift otherwise seed <<= 1; } } + // move to the next byte - ++ data; + ++data; length -= 8; } // process the odd bits - if(length > 0){ + if (length > 0) { // add the data with zero padding - seed ^= ((*data) &(0xFF << (8 - length))) << 24; + seed ^= ((*data) & (0xff << (8 - length))) << 24; + // for each added bit - for(index = 0; index < length; ++ index){ + for (index = 0; index < length; ++index) { // if the first bit is set - if(seed &0x80000000){ + if (seed & 0x80000000) { // shift and divide the checksum seed = (seed << 1) ^ ((uint32_t) CRC_DIVIDER_BE); - }else{ + } else { // shift otherwise seed <<= 1; @@ -115,37 +137,48 @@ } -uint32_t compute_crc32_le(uint32_t seed, uint8_t * data, size_t length){ +/** Computes CRC32 value in the little-endian environment. + * + * @param[in] seed Initial value. Often used as 0 or ~0. + * @param[in] data Pointer to the beginning of data to process. + * @param[in] length Length of the data in bits. + * @returns The computed CRC32 of the length bits of the data. + */ +uint32_t compute_crc32_le(uint32_t seed, uint8_t * data, size_t length) +{ size_t index; // process full bytes - while(length >= 8){ + while (length >= 8) { // add the data seed ^= (*data); + // for each added bit - for(index = 0; index < 8; ++ index){ + for (index = 0; index < 8; ++index) { // if the last bit is set - if(seed &1){ + if (seed & 1) { // shift and divide the checksum seed = (seed >> 1) ^ ((uint32_t) CRC_DIVIDER_LE); - }else{ + } else { // shift otherwise seed >>= 1; } } + // move to the next byte - ++ data; + ++data; length -= 8; } // process the odd bits - if(length > 0){ + if (length > 0) { // add the data with zero padding seed ^= (*data) >> (8 - length); - for(index = 0; index < length; ++ index){ + + for (index = 0; index < length; ++index) { // if the last bit is set - if(seed &1){ + if (seed & 1) { // shift and divide the checksum seed = (seed >> 1) ^ ((uint32_t) CRC_DIVIDER_LE); - }else{ + } else { // shift otherwise seed >>= 1; @@ -157,13 +190,33 @@ } -uint16_t flip_checksum(uint16_t checksum){ +/** Returns or flips the checksum if zero. + * + * @param[in] checksum The computed checksum. + * @returns The internet protocol header checksum. + * @returns 0xFFFF if the computed checksum is zero. + */ +uint16_t flip_checksum(uint16_t checksum) +{ // flip, zero is returned as 0xFFFF (not flipped) - checksum = ~ checksum; + checksum = ~checksum; return checksum ? checksum : IP_CHECKSUM_ZERO; } -uint16_t ip_checksum(uint8_t * data, size_t length){ +/** Computes the ip header checksum. + * + * To compute the checksum of a new packet, the checksum header field must be + * zero. To check the checksum of a received packet, the checksum may be left + * set. Zero will be returned in this case if valid. + * + * @param[in] data The header data. + * @param[in] length The header length in bytes. + * @returns The internet protocol header checksum. + * @returns 0xFFFF if the computed checksum is zero. + */ +uint16_t ip_checksum(uint8_t *data, size_t length) +{ // compute, compact and flip the data checksum - return flip_checksum(compact_checksum(compute_checksum(0, data, length))); + return flip_checksum(compact_checksum(compute_checksum(0, data, + length))); } Index: uspace/lib/net/include/net_checksum.h =================================================================== --- uspace/lib/net/include/net_checksum.h (revision b01f8788bb8fbbd617e4a54a67918bcf51f14239) +++ uspace/lib/net/include/net_checksum.h (revision 8d601dbff714a8e33d29f4c80051a46e4121abb4) @@ -27,84 +27,37 @@ */ -/** @addtogroup net - * @{ +/** @addtogroup libnet + * @{ */ /** @file - * General CRC and checksum computation. + * General CRC and checksum computation. */ -#ifndef __NET_CHECKSUM_H__ -#define __NET_CHECKSUM_H__ +#ifndef LIBNET_CHECKSUM_H_ +#define LIBNET_CHECKSUM_H_ #include - #include /** IP checksum value for computed zero checksum. - * Zero is returned as 0xFFFF (not flipped) + * Zero is returned as 0xFFFF (not flipped) */ -#define IP_CHECKSUM_ZERO 0xFFFFu +#define IP_CHECKSUM_ZERO 0xffffU -/** Computes CRC32 value. - * @param[in] seed Initial value. Often used as 0 or ~0. - * @param[in] data Pointer to the beginning of data to process. - * @param[in] length Length of the data in bits. - * @returns The computed CRC32 of the length bits of the data. - */ #ifdef ARCH_IS_BIG_ENDIAN - #define compute_crc32(seed, data, length) compute_crc32_be(seed, (uint8_t *) data, length) +#define compute_crc32(seed, data, length) \ + compute_crc32_be(seed, (uint8_t *) data, length) #else - #define compute_crc32(seed, data, length) compute_crc32_le(seed, (uint8_t *) data, length) +#define compute_crc32(seed, data, length) \ + compute_crc32_le(seed, (uint8_t *) data, length) #endif -/** Computes CRC32 value in the little-endian environment. - * @param[in] seed Initial value. Often used as 0 or ~0. - * @param[in] data Pointer to the beginning of data to process. - * @param[in] length Length of the data in bits. - * @returns The computed CRC32 of the length bits of the data. - */ -extern uint32_t compute_crc32_le(uint32_t seed, uint8_t * data, size_t length); - -/** Computes CRC32 value in the big-endian environment. - * @param[in] seed Initial value. Often used as 0 or ~0. - * @param[in] data Pointer to the beginning of data to process. - * @param[in] length Length of the data in bits. - * @returns The computed CRC32 of the length bits of the data. - */ -extern uint32_t compute_crc32_be(uint32_t seed, uint8_t * data, size_t length); - -/** Computes sum of the 2 byte fields. - * Padds one zero (0) byte if odd. - * @param[in] seed Initial value. Often used as 0 or ~0. - * @param[in] data Pointer to the beginning of data to process. - * @param[in] length Length of the data in bytes. - * @returns The computed checksum of the length bytes of the data. - */ -extern uint32_t compute_checksum(uint32_t seed, uint8_t * data, size_t length); - -/** Compacts the computed checksum to the 16 bit number adding the carries. - * @param[in] sum Computed checksum. - * @returns Compacted computed checksum to the 16 bits. - */ -extern uint16_t compact_checksum(uint32_t sum); - -/** Returns or flips the checksum if zero. - * @param[in] checksum The computed checksum. - * @returns The internet protocol header checksum. - * @returns 0xFFFF if the computed checksum is zero. - */ -extern uint16_t flip_checksum(uint16_t checksum); - -/** Computes the ip header checksum. - * To compute the checksum of a new packet, the checksum header field must be zero. - * To check the checksum of a received packet, the checksum may be left set. - * The zero (0) value will be returned in this case if valid. - * @param[in] data The header data. - * @param[in] length The header length in bytes. - * @returns The internet protocol header checksum. - * @returns 0xFFFF if the computed checksum is zero. - */ -extern uint16_t ip_checksum(uint8_t * data, size_t length); +extern uint32_t compute_crc32_le(uint32_t, uint8_t *, size_t); +extern uint32_t compute_crc32_be(uint32_t, uint8_t *, size_t); +extern uint32_t compute_checksum(uint32_t, uint8_t *, size_t); +extern uint16_t compact_checksum(uint32_t); +extern uint16_t flip_checksum(uint16_t); +extern uint16_t ip_checksum(uint8_t *, size_t); #endif