/**
* Called from ip_input() if a new IGMP packet is received.
*
* @param p received igmp packet, p->payload pointing to the igmp header
* @param inp network interface on which the packet was received
* @param dest destination ip address of the igmp packet
*/
void
igmp_input(struct pbuf *p, struct netif *inp, const ip4_addr_t *dest)
{
struct igmp_msg* igmp;
struct igmp_group* group;
struct igmp_group* groupref;
IGMP_STATS_INC(igmp.recv);
/* Note that the length CAN be greater than 8 but only 8 are used - All are included in the checksum */
if (p->len < IGMP_MINLEN) {
pbuf_free(p);
IGMP_STATS_INC(igmp.lenerr);
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: length error\n"));
return;
}
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: message from "));
ip4_addr_debug_print(IGMP_DEBUG, &(ip4_current_header()->src));
LWIP_DEBUGF(IGMP_DEBUG, (" to address "));
ip4_addr_debug_print(IGMP_DEBUG, &(ip4_current_header()->dest));
LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", (void*)inp));
/* Now calculate and check the checksum */
igmp = (struct igmp_msg *)p->payload;
if (inet_chksum(igmp, p->len)) {
pbuf_free(p);
IGMP_STATS_INC(igmp.chkerr);
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: checksum error\n"));
return;
}
/* Packet is ok so find an existing group */
group = igmp_lookfor_group(inp, dest); /* use the destination IP address of incoming packet */
/* If group can be found or create... */
if (!group) {
pbuf_free(p);
IGMP_STATS_INC(igmp.drop);
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP frame not for us\n"));
return;
}
/* NOW ACT ON THE INCOMING MESSAGE TYPE... */
switch (igmp->igmp_msgtype) {
case IGMP_MEMB_QUERY:
/* IGMP_MEMB_QUERY to the "all systems" address ? */
if ((ip4_addr_cmp(dest, &allsystems)) && ip4_addr_isany(&igmp->igmp_group_address)) {
/* THIS IS THE GENERAL QUERY */
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: General IGMP_MEMB_QUERY on \"ALL SYSTEMS\" address (224.0.0.1) [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
if (igmp->igmp_maxresp == 0) {
IGMP_STATS_INC(igmp.rx_v1);
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: got an all hosts query with time== 0 - this is V1 and not implemented - treat as v2\n"));
igmp->igmp_maxresp = IGMP_V1_DELAYING_MEMBER_TMR;
} else {
IGMP_STATS_INC(igmp.rx_general);
}
groupref = igmp_group_list;
while (groupref) {
/* Do not send messages on the all systems group address! */
if ((groupref->netif == inp) && (!(ip4_addr_cmp(&(groupref->group_address), &allsystems)))) {
igmp_delaying_member(groupref, igmp->igmp_maxresp);
}
groupref = groupref->next;
}
} else {
/* IGMP_MEMB_QUERY to a specific group ? */
if (!ip4_addr_isany(&igmp->igmp_group_address)) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP_MEMB_QUERY to a specific group "));
ip4_addr_debug_print(IGMP_DEBUG, &igmp->igmp_group_address);
if (ip4_addr_cmp(dest, &allsystems)) {
ip4_addr_t groupaddr;
LWIP_DEBUGF(IGMP_DEBUG, (" using \"ALL SYSTEMS\" address (224.0.0.1) [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
/* we first need to re-look for the group since we used dest last time */
ip4_addr_copy(groupaddr, igmp->igmp_group_address);
group = igmp_lookfor_group(inp, &groupaddr);
} else {
LWIP_DEBUGF(IGMP_DEBUG, (" with the group address as destination [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
}
if (group != NULL) {
IGMP_STATS_INC(igmp.rx_group);
igmp_delaying_member(group, igmp->igmp_maxresp);
} else {
IGMP_STATS_INC(igmp.drop);
}
} else {
IGMP_STATS_INC(igmp.proterr);
}
}
break;
case IGMP_V2_MEMB_REPORT:
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP_V2_MEMB_REPORT\n"));
IGMP_STATS_INC(igmp.rx_report);
if (group->group_state == IGMP_GROUP_DELAYING_MEMBER) {
/* This is on a specific group we have already looked up */
group->timer = 0; /* stopped */
group->group_state = IGMP_GROUP_IDLE_MEMBER;
group->last_reporter_flag = 0;
}
break;
default:
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: unexpected msg %d in state %d on group %p on if %p\n",
igmp->igmp_msgtype, group->group_state, (void*)&group, (void*)group->netif));
IGMP_STATS_INC(igmp.proterr);
break;
}
pbuf_free(p);
return;
}
/**
* Processes ICMP input packets, called from ip_input().
*
* Currently only processes icmp echo requests and sends
* out the echo response.
*
* @param p the icmp echo request packet, p->payload pointing to the icmp header
* @param inp the netif on which this packet was received
*/
void
icmp_input(struct pbuf *p, struct netif *inp)
{
u8_t type;
#ifdef LWIP_DEBUG
u8_t code;
#endif /* LWIP_DEBUG */
struct icmp_echo_hdr *iecho;
const struct ip_hdr *iphdr_in;
struct ip_hdr *iphdr;
s16_t hlen;
const ip4_addr_t* src;
ICMP_STATS_INC(icmp.recv);
MIB2_STATS_INC(mib2.icmpinmsgs);
iphdr_in = ip4_current_header();
hlen = IPH_HL(iphdr_in) * 4;
if (p->len < sizeof(u16_t)*2) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len));
goto lenerr;
}
type = *((u8_t *)p->payload);
#ifdef LWIP_DEBUG
code = *(((u8_t *)p->payload)+1);
#endif /* LWIP_DEBUG */
switch (type) {
case ICMP_ER:
/* This is OK, echo reply might have been parsed by a raw PCB
(as obviously, an echo request has been sent, too). */
break;
case ICMP_ECHO:
src = ip4_current_dest_addr();
/* multicast destination address? */
if (ip_addr_ismulticast(ip_current_dest_addr())) {
#if LWIP_MULTICAST_PING
/* For multicast, use address of receiving interface as source address */
src = netif_ip4_addr(inp);
#else /* LWIP_MULTICAST_PING */
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast pings\n"));
goto icmperr;
#endif /* LWIP_MULTICAST_PING */
}
/* broadcast destination address? */
if (ip_addr_isbroadcast(ip_current_dest_addr(), ip_current_netif())) {
#if LWIP_BROADCAST_PING
/* For broadcast, use address of receiving interface as source address */
src = netif_ip4_addr(inp);
#else /* LWIP_BROADCAST_PING */
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to broadcast pings\n"));
goto icmperr;
#endif /* LWIP_BROADCAST_PING */
}
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));
goto lenerr;
}
#if CHECKSUM_CHECK_ICMP
IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_ICMP) {
if (inet_chksum_pbuf(p) != 0) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));
pbuf_free(p);
ICMP_STATS_INC(icmp.chkerr);
MIB2_STATS_INC(mib2.icmpinerrors);
return;
}
}
#endif
#if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN))) {
/* p is not big enough to contain link headers
* allocate a new one and copy p into it
*/
struct pbuf *r;
/* allocate new packet buffer with space for link headers */
r = pbuf_alloc(PBUF_LINK, p->tot_len + hlen, PBUF_RAM);
if (r == NULL) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n"));
goto icmperr;
}
LWIP_ASSERT("check that first pbuf can hold struct the ICMP header",
(r->len >= hlen + sizeof(struct icmp_echo_hdr)));
/* copy the ip header */
MEMCPY(r->payload, iphdr_in, hlen);
iphdr = (struct ip_hdr *)r->payload;
/* switch r->payload back to icmp header */
if (pbuf_header(r, -hlen)) {
LWIP_ASSERT("icmp_input: moving r->payload to icmp header failed\n", 0);
goto icmperr;
}
/* copy the rest of the packet without ip header */
if (pbuf_copy(r, p) != ERR_OK) {
LWIP_ASSERT("icmp_input: copying to new pbuf failed\n", 0);
goto icmperr;
}
/* free the original p */
pbuf_free(p);
/* we now have an identical copy of p that has room for link headers */
p = r;
} else {
/* restore p->payload to point to icmp header */
if (pbuf_header(p, -(s16_t)(PBUF_IP_HLEN + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN))) {
LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
goto icmperr;
}
}
#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
/* At this point, all checks are OK. */
/* We generate an answer by switching the dest and src ip addresses,
* setting the icmp type to ECHO_RESPONSE and updating the checksum. */
iecho = (struct icmp_echo_hdr *)p->payload;
if(pbuf_header(p, hlen)) {
LWIP_ASSERT("Can't move over header in packet", 0);
} else {
err_t ret;
iphdr = (struct ip_hdr*)p->payload;
ip4_addr_copy(iphdr->src, *src);
ip4_addr_copy(iphdr->dest, *ip4_current_src_addr());
ICMPH_TYPE_SET(iecho, ICMP_ER);
#if CHECKSUM_GEN_ICMP
IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_ICMP) {
/* adjust the checksum */
if (iecho->chksum > PP_HTONS(0xffffU - (ICMP_ECHO << 8))) {
iecho->chksum += PP_HTONS(ICMP_ECHO << 8) + 1;
} else {
iecho->chksum += PP_HTONS(ICMP_ECHO << 8);
}
}
#if LWIP_CHECKSUM_CTRL_PER_NETIF
else {
iecho->chksum = 0;
}
#endif /* LWIP_CHECKSUM_CTRL_PER_NETIF */
#else /* CHECKSUM_GEN_ICMP */
iecho->chksum = 0;
#endif /* CHECKSUM_GEN_ICMP */
/* Set the correct TTL and recalculate the header checksum. */
IPH_TTL_SET(iphdr, ICMP_TTL);
IPH_CHKSUM_SET(iphdr, 0);
#if CHECKSUM_GEN_IP
IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_IP) {
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
}
#endif /* CHECKSUM_GEN_IP */
ICMP_STATS_INC(icmp.xmit);
/* increase number of messages attempted to send */
MIB2_STATS_INC(mib2.icmpoutmsgs);
/* increase number of echo replies attempted to send */
MIB2_STATS_INC(mib2.icmpoutechoreps);
/* send an ICMP packet */
ret = ip4_output_if(p, src, IP_HDRINCL,
ICMP_TTL, 0, IP_PROTO_ICMP, inp);
if (ret != ERR_OK) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %c.\n", ret));
}
}
