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bug #33634 ip_forward() have a faulty behaviour: Added pbuf flags to mark incoming packets as link-layer broadcast/multicast. Also added code to allow ip_forward() to forward non-broadcast packets to the input netif (set IP_FORWARD_ALLOW_TX_ON_RX_NETIF==1).

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This commit is contained in:
Simon Goldschmidt
2011-07-21 21:47:25 +02:00
parent 860072aaaf
commit 78ac382fdf
5 changed files with 127 additions and 4 deletions
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57
src/core/ipv4/ip4.c
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@@ -113,8 +113,15 @@ ip_route(ip_addr_t *dest)
{
struct netif *netif;
#ifdef LWIP_HOOK_IP4_ROUTE
netif = LWIP_HOOK_IP4_ROUTE(dest);
if (netif != NULL) {
return netif;
}
#endif
/* iterate through netifs */
for(netif = netif_list; netif != NULL; netif = netif->next) {
for (netif = netif_list; netif != NULL; netif = netif->next) {
/* network mask matches? */
if (netif_is_up(netif)) {
if (ip_addr_netcmp(dest, &(netif->ip_addr), &(netif->netmask))) {
@@ -135,6 +142,41 @@ ip_route(ip_addr_t *dest)
}
#if IP_FORWARD
/**
* Determine whether an IP address is in a reserved set of addresses
* that may not be forwarded, or whether datagrams to that destination
* may be forwarded.
* @param p the packet to forward
* @param dest the destination IP address
* @return 1: can forward 0: discard
*/
static int
ip_canforward(struct pbuf *p)
{
u32_t addr = ip4_addr_get_u32(ip_current_dest_addr());
if (p->flags & PBUF_FLAG_LLBCAST) {
/* don't route link-layer broadcasts */
return 0;
}
if ((p->flags & PBUF_FLAG_LLMCAST) && !IP_MULTICAST(addr)) {
/* don't route link-layer multicasts unless the destination address is an IP
multicast address */
return 0;
}
if (IP_EXPERIMENTAL(addr)) {
return 0;
}
if (IP_CLASSA(addr)) {
u32_t net = addr & IP_CLASSA_NET;
if ((net == 0) || (net == (IP_LOOPBACKNET << IP_CLASSA_NSHIFT))) {
/* don't route loopback packets */
return 0;
}
}
return 1;
}
/**
* Forwards an IP packet. It finds an appropriate route for the
* packet, decrements the TTL value of the packet, adjusts the
@@ -151,6 +193,10 @@ ip_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
PERF_START;
if (!ip_canforward(p)) {
goto return_noroute;
}
/* RFC3927 2.7: do not forward link-local addresses */
if (ip_addr_islinklocal(ip_current_dest_addr())) {
LWIP_DEBUGF(IP_DEBUG, ("ip_forward: not forwarding LLA %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
@@ -167,12 +213,14 @@ ip_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
ip4_addr3_16(ip_current_dest_addr()), ip4_addr4_16(ip_current_dest_addr())));
goto return_noroute;
}
#if !IP_FORWARD_ALLOW_TX_ON_RX_NETIF
/* Do not forward packets onto the same network interface on which
* they arrived. */
if (netif == inp) {
LWIP_DEBUGF(IP_DEBUG, ("ip_forward: not bouncing packets back on incoming interface.\n"));
goto return_noroute;
}
#endif /* IP_FORWARD_ALLOW_TX_ON_RX_NETIF */
/* decrement TTL */
IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
@@ -252,6 +300,13 @@ ip_input(struct pbuf *p, struct netif *inp)
return ERR_OK;
}
#ifdef LWIP_HOOK_IP4_INPUT
if (LWIP_HOOK_IP4_INPUT(p, inp)) {
/* the packet has been eaten */
return ERR_OK;
}
#endif
/* obtain IP header length in number of 32-bit words */
iphdr_hlen = IPH_HL(iphdr);
/* calculate IP header length in bytes */