/***
* common reply function
*/
static void rt_icmp_send_reply(struct icmp_bxm *icmp_param, struct rtskb *skb)
{
struct dest_route rt;
int err;
icmp_param->head.icmph.checksum = 0;
icmp_param->csum = 0;
/* route back to the source address via the incoming device */
if (rt_ip_route_output(&rt, skb->nh.iph->saddr,
skb->rtdev->local_ip) != 0)
return;
rt_socket_reference(icmp_socket);
err = rt_ip_build_xmit(icmp_socket, rt_icmp_glue_reply_bits, icmp_param,
sizeof(struct icmphdr) + icmp_param->data_len,
&rt, MSG_DONTWAIT);
if (err)
rt_socket_dereference(icmp_socket);
rtdev_dereference(rt.rtdev);
RTNET_ASSERT(err == 0,
rtdm_printk("RTnet: %s() error in xmit\n", __FUNCTION__););
/*
* This function returns an rtskb that contains the complete, accumulated IP message.
* If not all fragments of the IP message have been received yet, it returns NULL
* Note: the IP header must have already been pulled from the rtskb!
* */
struct rtskb *rt_ip_defrag(struct rtskb *skb, struct rtinet_protocol *ipprot)
{
unsigned int more_frags;
unsigned int offset;
struct rtsocket *sock;
struct iphdr *iph = skb->nh.iph;
int ret;
counter++;
/* Parse the IP header */
offset = ntohs(iph->frag_off);
more_frags = offset & IP_MF;
offset &= IP_OFFSET;
offset <<= 3; /* offset is in 8-byte chunks */
/* First fragment? */
if (offset == 0)
{
/* Get the destination socket */
if ((sock = ipprot->dest_socket(skb)) == NULL) {
/* Drop the rtskb */
kfree_rtskb(skb);
return NULL;
}
/* Acquire the rtskb at the expense of the protocol pool */
ret = rtskb_acquire(skb, &sock->skb_pool);
/* socket is now implicitely locked by the rtskb */
rt_socket_dereference(sock);
if (ret != 0) {
/* Drop the rtskb */
kfree_rtskb(skb);
} else {
/* Allocates a new collector */
alloc_collector(skb, sock);
}
return NULL;
}
else
{
/* Add to an existing collector */
return add_to_collector(skb, offset, more_frags);
}
}
/***
* rt_ip_local_deliver
*/
static inline int rt_ip_local_deliver(struct rtskb *skb)
{
struct iphdr *iph = skb->nh.iph;
unsigned short protocol = iph->protocol;
struct rtinet_protocol *ipprot;
struct rtsocket *sock;
int ret;
ipprot = rt_inet_protocols[rt_inet_hashkey(protocol)];
/* Check if we are supporting the protocol */
if ((ipprot != NULL) && (ipprot->protocol == protocol))
{
__rtskb_pull(skb, iph->ihl*4);
/* Point into the IP datagram, just past the header. */
skb->h.raw = skb->data;
/* Reassemble IP fragments */
if (iph->frag_off & htons(IP_MF|IP_OFFSET)) {
skb = rt_ip_defrag(skb, ipprot);
if (!skb)
return 0;
} else {
/* Get the destination socket */
if ((sock = ipprot->dest_socket(skb)) == NULL) {
kfree_rtskb(skb);
return 0;
}
/* Acquire the rtskb at the expense of the protocol pool */
ret = rtskb_acquire(skb, &sock->skb_pool);
/* Socket is now implicitely locked by the rtskb */
rt_socket_dereference(sock);
if (ret != 0) {
kfree_rtskb(skb);
return 0;
}
}
/* Deliver the packet to the next layer */
ret = ipprot->rcv_handler(skb);
} else {
#ifdef CONFIG_RTNET_ADDON_PROXY
/* If a fallback handler for IP protocol has been installed,
* call it! */
if (ip_fallback_handler) {
ret = ip_fallback_handler(skb);
if (ret) {
rtos_print("RTnet: fallback handler failed\n");
}
return ret;
}
#endif /* CONFIG_RTNET_ADDON_PROXY */
rtos_print("RTnet: no protocol found\n");
kfree_rtskb(skb);
ret = 0;
}
return ret;
}
