diff options
| -rw-r--r-- | Makefile.target | 2 | ||||
| -rw-r--r-- | net-checksum.c | 87 | ||||
| -rw-r--r-- | net.h | 7 |
3 files changed, 95 insertions, 1 deletions
diff --git a/Makefile.target b/Makefile.target index ff105c1fa..42162c393 100644 --- a/Makefile.target +++ b/Makefile.target @@ -472,7 +472,7 @@ endif #CONFIG_DARWIN_USER # System emulator target ifndef CONFIG_USER_ONLY -OBJS=vl.o osdep.o monitor.o pci.o loader.o isa_mmio.o machine.o +OBJS=vl.o osdep.o monitor.o pci.o loader.o isa_mmio.o machine.o net-checksum.o ifdef CONFIG_WIN32 OBJS+=block-raw-win32.o else diff --git a/net-checksum.c b/net-checksum.c new file mode 100644 index 000000000..a4806558e --- /dev/null +++ b/net-checksum.c @@ -0,0 +1,87 @@ +/* + * IP checksumming functions. + * (c) 2008 Gerd Hoffmann <kraxel@redhat.com> + * + * 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; under version 2 of the License. + * + * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include "hw/hw.h" +#include "net.h" + +#define PROTO_TCP 6 +#define PROTO_UDP 17 + +uint32_t net_checksum_add(int len, uint8_t *buf) +{ + uint32_t sum = 0; + int i; + + for (i = 0; i < len; i++) { + if (i & 1) + sum += (uint32_t)buf[i]; + else + sum += (uint32_t)buf[i] << 8; + } + return sum; +} + +uint16_t net_checksum_finish(uint32_t sum) +{ + while (sum>>16) + sum = (sum & 0xFFFF)+(sum >> 16); + return ~sum; +} + +uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto, + uint8_t *addrs, uint8_t *buf) +{ + uint32_t sum = 0; + + sum += net_checksum_add(length, buf); // payload + sum += net_checksum_add(8, addrs); // src + dst address + sum += proto + length; // protocol & length + return net_checksum_finish(sum); +} + +void net_checksum_calculate(uint8_t *data, int length) +{ + int hlen, plen, proto, csum_offset; + uint16_t csum; + + if ((data[14] & 0xf0) != 0x40) + return; /* not IPv4 */ + hlen = (data[14] & 0x0f) * 4; + plen = (data[16] << 8 | data[17]) - hlen; + proto = data[23]; + + switch (proto) { + case PROTO_TCP: + csum_offset = 16; + break; + case PROTO_UDP: + csum_offset = 6; + break; + default: + return; + } + + if (plen < csum_offset+2) + return; + + data[14+hlen+csum_offset] = 0; + data[14+hlen+csum_offset+1] = 0; + csum = net_checksum_tcpudp(plen, proto, data+14+12, data+14+hlen); + data[14+hlen+csum_offset] = csum >> 8; + data[14+hlen+csum_offset+1] = csum & 0xff; +} @@ -48,4 +48,11 @@ struct NICInfo { extern int nb_nics; extern NICInfo nd_table[MAX_NICS]; +/* checksumming functions (net-checksum.c) */ +uint32_t net_checksum_add(int len, uint8_t *buf); +uint16_t net_checksum_finish(uint32_t sum); +uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto, + uint8_t *addrs, uint8_t *buf); +void net_checksum_calculate(uint8_t *data, int length); + #endif |