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Annotation of qemu/roms/ipxe/src/net/tcpip.c, revision 1.1

1.1     ! root        1: #include <stdint.h>
        !             2: #include <string.h>
        !             3: #include <errno.h>
        !             4: #include <byteswap.h>
        !             5: #include <ipxe/iobuf.h>
        !             6: #include <ipxe/tables.h>
        !             7: #include <ipxe/tcpip.h>
        !             8: 
        !             9: /** @file
        !            10:  *
        !            11:  * Transport-network layer interface
        !            12:  *
        !            13:  * This file contains functions and utilities for the
        !            14:  * TCP/IP transport-network layer interface
        !            15:  */
        !            16: 
        !            17: FILE_LICENCE ( GPL2_OR_LATER );
        !            18: 
        !            19: /** Process a received TCP/IP packet
        !            20:  *
        !            21:  * @v iobuf            I/O buffer
        !            22:  * @v tcpip_proto      Transport-layer protocol number
        !            23:  * @v st_src           Partially-filled source address
        !            24:  * @v st_dest          Partially-filled destination address
        !            25:  * @v pshdr_csum       Pseudo-header checksum
        !            26:  * @ret rc             Return status code
        !            27:  *
        !            28:  * This function expects a transport-layer segment from the network
        !            29:  * layer.  The network layer should fill in as much as it can of the
        !            30:  * source and destination addresses (i.e. it should fill in the
        !            31:  * address family and the network-layer addresses, but leave the ports
        !            32:  * and the rest of the structures as zero).
        !            33:  */
        !            34: int tcpip_rx ( struct io_buffer *iobuf, uint8_t tcpip_proto, 
        !            35:               struct sockaddr_tcpip *st_src,
        !            36:               struct sockaddr_tcpip *st_dest,
        !            37:               uint16_t pshdr_csum ) {
        !            38:        struct tcpip_protocol *tcpip;
        !            39: 
        !            40:        /* Hand off packet to the appropriate transport-layer protocol */
        !            41:        for_each_table_entry ( tcpip, TCPIP_PROTOCOLS ) {
        !            42:                if ( tcpip->tcpip_proto == tcpip_proto ) {
        !            43:                        DBG ( "TCP/IP received %s packet\n", tcpip->name );
        !            44:                        return tcpip->rx ( iobuf, st_src, st_dest, pshdr_csum );
        !            45:                }
        !            46:        }
        !            47: 
        !            48:        DBG ( "Unrecognised TCP/IP protocol %d\n", tcpip_proto );
        !            49:        free_iob ( iobuf );
        !            50:        return -EPROTONOSUPPORT;
        !            51: }
        !            52: 
        !            53: /** Transmit a TCP/IP packet
        !            54:  *
        !            55:  * @v iobuf            I/O buffer
        !            56:  * @v tcpip_protocol   Transport-layer protocol
        !            57:  * @v st_src           Source address, or NULL to use route default
        !            58:  * @v st_dest          Destination address
        !            59:  * @v netdev           Network device to use if no route found, or NULL
        !            60:  * @v trans_csum       Transport-layer checksum to complete, or NULL
        !            61:  * @ret rc             Return status code
        !            62:  */
        !            63: int tcpip_tx ( struct io_buffer *iobuf, struct tcpip_protocol *tcpip_protocol,
        !            64:               struct sockaddr_tcpip *st_src, struct sockaddr_tcpip *st_dest,
        !            65:               struct net_device *netdev, uint16_t *trans_csum ) {
        !            66:        struct tcpip_net_protocol *tcpip_net;
        !            67: 
        !            68:        /* Hand off packet to the appropriate network-layer protocol */
        !            69:        for_each_table_entry ( tcpip_net, TCPIP_NET_PROTOCOLS ) {
        !            70:                if ( tcpip_net->sa_family == st_dest->st_family ) {
        !            71:                        DBG ( "TCP/IP sending %s packet\n", tcpip_net->name );
        !            72:                        return tcpip_net->tx ( iobuf, tcpip_protocol, st_src,
        !            73:                                               st_dest, netdev, trans_csum );
        !            74:                }
        !            75:        }
        !            76:        
        !            77:        DBG ( "Unrecognised TCP/IP address family %d\n", st_dest->st_family );
        !            78:        free_iob ( iobuf );
        !            79:        return -EAFNOSUPPORT;
        !            80: }
        !            81: 
        !            82: /**
        !            83:  * Calculate continued TCP/IP checkum
        !            84:  *
        !            85:  * @v partial          Checksum of already-summed data, in network byte order
        !            86:  * @v data             Data buffer
        !            87:  * @v len              Length of data buffer
        !            88:  * @ret cksum          Updated checksum, in network byte order
        !            89:  *
        !            90:  * Calculates a TCP/IP-style 16-bit checksum over the data block.  The
        !            91:  * checksum is returned in network byte order.
        !            92:  *
        !            93:  * This function may be used to add new data to an existing checksum.
        !            94:  * The function assumes that both the old data and the new data start
        !            95:  * on even byte offsets; if this is not the case then you will need to
        !            96:  * byte-swap either the input partial checksum, the output checksum,
        !            97:  * or both.  Deciding which to swap is left as an exercise for the
        !            98:  * interested reader.
        !            99:  */
        !           100: uint16_t tcpip_continue_chksum ( uint16_t partial, const void *data,
        !           101:                                 size_t len ) {
        !           102:        unsigned int cksum = ( ( ~partial ) & 0xffff );
        !           103:        unsigned int value;
        !           104:        unsigned int i;
        !           105:        
        !           106:        for ( i = 0 ; i < len ; i++ ) {
        !           107:                value = * ( ( uint8_t * ) data + i );
        !           108:                if ( i & 1 ) {
        !           109:                        /* Odd bytes: swap on little-endian systems */
        !           110:                        value = be16_to_cpu ( value );
        !           111:                } else {
        !           112:                        /* Even bytes: swap on big-endian systems */
        !           113:                        value = le16_to_cpu ( value );
        !           114:                }
        !           115:                cksum += value;
        !           116:                if ( cksum > 0xffff )
        !           117:                        cksum -= 0xffff;
        !           118:        }
        !           119:        
        !           120:        return ( ~cksum );
        !           121: }
        !           122: 
        !           123: /**
        !           124:  * Calculate TCP/IP checkum
        !           125:  *
        !           126:  * @v data             Data buffer
        !           127:  * @v len              Length of data buffer
        !           128:  * @ret cksum          Checksum, in network byte order
        !           129:  *
        !           130:  * Calculates a TCP/IP-style 16-bit checksum over the data block.  The
        !           131:  * checksum is returned in network byte order.
        !           132:  */
        !           133: uint16_t tcpip_chksum ( const void *data, size_t len ) {
        !           134:        return tcpip_continue_chksum ( TCPIP_EMPTY_CSUM, data, len );
        !           135: }

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