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ipv4: checksumming and processing

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Matheus
2024-04-07 16:32:01 -03:00
parent 219635a48a
commit 12612218ad
2 changed files with 62 additions and 5 deletions
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kernel-src/io/net/eth.c
+1 -2
View File
@@ -15,12 +15,11 @@ void eth_process(netdev_t *netdev, void *buffer) {
if (!(MAC_EQUAL(&dst, &netdev->mac) || MAC_EQUAL(&dst, &broadcast)))
return;
printf("our machine!\n");
void *nextbuff = (void *)((uintptr_t)buffer + sizeof(ethframe_t));
switch (be_to_cpu_w(frame->type)) {
case ETH_PROTO_IP:
ipv4_process(netdev, nextbuff);
break;
case ETH_PROTO_ARP:
arp_process(netdev, nextbuff);
kernel-src/io/net/ipv4.c
+61 -3
View File
@@ -4,6 +4,7 @@
#include <logging.h>
#include <mutex.h>
#include <kernel/alloc.h>
#include <kernel/abi.h>
typedef struct {
netdev_t *netdev;
@@ -79,6 +80,27 @@ int ipv4_addroute(netdev_t *netdev, uint32_t addr, uint32_t gateway, uint32_t ma
#define FLAG_MF 1
// offset has to be a multiple of 8
#define FLAGS_FRAGOFFSET(flg, offset) (((flg) << 13) | ((offset) >> 3))
#define GET_FLAGS(x) (((x) >> 13) & 0x7)
#define GET_FRAGOFFSET(x) ((x) & 0x1fff)
static int checksum(void *buffer, size_t size) {
uint16_t *p = buffer;
int sum = 0;
int i;
for (int i = 0; i < (size & ~(1lu)); i += 2) {
sum += be_to_cpu_w(p[i >> 1]);
}
if (size & 1) {
sum += ((uint8_t *)p)[i];
}
sum = (sum >> 16) + (sum & 0xffff);
sum += sum >> 16;
uint16_t ret = ~sum;
return ret;
}
static int dispatch_fragment(netdev_t *netdev, netdesc_t fragdesc,
uintmax_t fragmentoffset, size_t fragmentlen, int id, uint32_t ip, mac_t mac, int proto, bool last) {
@@ -90,15 +112,50 @@ static int dispatch_fragment(netdev_t *netdev, netdesc_t fragdesc,
.flags_fragoffset = cpu_to_be_w(FLAGS_FRAGOFFSET(!last ? FLAG_MF : 0, fragmentoffset)),
.timetolive = 0xff,
.protocol = proto,
.framechecksum = 0xfefe, // TODO checksum
.srcaddr = netdev->ip, // TODO src addr
.framechecksum = 0,
.srcaddr = cpu_to_be_d(netdev->ip),
.dstaddr = cpu_to_be_d(ip)
};
frame.framechecksum = cpu_to_be_w(checksum(&frame, sizeof(frame)));
memcpy((void *)((uintptr_t)fragdesc.address + fragdesc.curroffset), &frame, sizeof(ipv4frame_t));
return netdev->sendpacket(netdev, fragdesc, mac, ETH_PROTO_IP);
}
void ipv4_process(netdev_t *netdev, void *buff) {
ipv4frame_t *frame = buff;
if (checksum(frame, sizeof(ipv4frame_t)) != 0) {
return;
}
if (frame->version_length != VERSION_LENGTH(4, 5))
return;
uint16_t flagsfrag = be_to_cpu_w(frame->flags_fragoffset);
if ((GET_FLAGS(flagsfrag) & FLAG_MF) || (GET_FRAGOFFSET(flagsfrag) > 0)) {
printf("ipv4: reassembly not yet supported\n");
return;
}
uint32_t dstip = be_to_cpu_d(frame->dstaddr);
uint32_t srcip = be_to_cpu_d(frame->srcaddr);
if (dstip != IPV4_BROADCAST_ADDRESS && dstip != netdev->ip)
return;
void *nextbuff = (void *)((uintptr_t)buff + sizeof(ipv4frame_t));
switch (frame->protocol) {
case IPV4_PROTO_UDP:
udp_process(netdev, nextbuff, srcip);
break;
}
return;
}
int ipv4_sendpacket(void *buffer, size_t packetsize, uint32_t ip, int proto, netdev_t *broadcastdev) {
if ((packetsize + sizeof(ipv4frame_t)) > 65535)
return EMSGSIZE;
@@ -134,7 +191,8 @@ int ipv4_sendpacket(void *buffer, size_t packetsize, uint32_t ip, int proto, net
if (e)
return e;
memcpy((void *)((uintptr_t)fragdesc.address + sizeof(ipv4frame_t)), (void *)((uintptr_t)buffer + i * devfragmentsize), fragmentlen);
memcpy((void *)((uintptr_t)fragdesc.address + fragdesc.curroffset + sizeof(ipv4frame_t)), (void *)((uintptr_t)buffer + i * devfragmentsize), fragmentlen);
e = dispatch_fragment(netdev, fragdesc, i * devfragmentsize, fragmentlen, 0x1234, ip, mac, proto, i == fragmentcount - 1);
// TODO unallocate desc
if (e)