![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to tcpip.c CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [Qemu by Fabrice Bellard] / qemu / roms / ipxe / src / net|
Return to tcpip.c CVS log | Up to [Qemu by Fabrice Bellard] / qemu / roms / ipxe / src / net |
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: }
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.