void send_ping(router_t *router, addr_ip_t dest_ip, addr_ip_t src_ip, uint16_t id, uint16_t count) {
int len = IPV4_HEADER_LENGTH+8;
byte *payload = malloc_or_die(len*sizeof(byte)); //Free'd (below)
struct ip_hdr *iphdr = (void *)payload;
IPH_VHLTOS_SET(iphdr, 4, 5, 0);
IPH_LEN_SET(iphdr, htons(len));
IPH_ID_SET(iphdr, 0);
IPH_OFFSET_SET(iphdr, 0);
IPH_TTL_SET(iphdr, 64);
IPH_PROTO_SET(iphdr, 1);
iphdr->src.addr = src_ip;
iphdr->dest.addr = dest_ip;
IPH_CHKSUM_SET(iphdr, 0);
IPH_CHKSUM_SET(iphdr, htons(calc_checksum(payload, IPV4_HEADER_LENGTH)));
struct icmp_echo_hdr *pihdr = (void *)payload+IPV4_HEADER_LENGTH;
ICMPH_TYPE_SET(pihdr, ICMP_TYPE_ECHO_REQUEST);
ICMPH_CODE_SET(pihdr, 0);
pihdr->id = id;
pihdr->seqno = count;
ICMPH_CHKSUM_SET(pihdr, 0);
ICMPH_CHKSUM_SET(pihdr, htons(calc_checksum(payload+IPV4_HEADER_LENGTH, 8)));
send_packet(payload, src_ip, dest_ip, len, FALSE, FALSE);
free(payload);
}
/*-----------------------------------------------------------------------------------*/
err_t
ip_output_if(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
u8_t ttl,
u8_t proto, struct netif *netif)
{
static struct ip_hdr *iphdr;
static u16_t ip_id = 0;
if(dest != IP_HDRINCL) {
if(pbuf_header(p, IP_HLEN)) {
DEBUGF(IP_DEBUG, ("ip_output: not enough room for IP header in pbuf\n"));
#ifdef IP_STATS
++stats.ip.err;
#endif /* IP_STATS */
pbuf_free(p);
return ERR_BUF;
}
iphdr = p->payload;
IPH_TTL_SET(iphdr, ttl);
IPH_PROTO_SET(iphdr, proto);
ip_addr_set(&(iphdr->dest), dest);
IPH_VHLTOS_SET(iphdr, 4, IP_HLEN / 4, 0);
IPH_LEN_SET(iphdr, htons(p->tot_len));
IPH_OFFSET_SET(iphdr, htons(IP_DF));
IPH_ID_SET(iphdr, htons(++ip_id));
if(ip_addr_isany(src)) {
ip_addr_set(&(iphdr->src), &(netif->ip_addr));
} else {
ip_addr_set(&(iphdr->src), src);
}
IPH_CHKSUM_SET(iphdr, 0);
#if CHECKSUM_GEN_IP
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
#endif
} else {
iphdr = p->payload;
dest = &(iphdr->dest);
}
#ifdef IP_STATS
stats.ip.xmit++;
#endif /* IP_STATS */
DEBUGF(IP_DEBUG, ("ip_output_if: %c%c ", netif->name[0], netif->name[1]));
#if IP_DEBUG
ip_debug_print(p);
#endif /* IP_DEBUG */
return netif->output(netif, p, dest);
}
/**
* Sends an IP packet on a network interface. This function constructs
* the IP header and calculates the IP header checksum. If the source
* IP address is NULL, the IP address of the outgoing network
* interface is filled in as source address.
* If the destination IP address is IP_HDRINCL, p is assumed to already
* include an IP header and p->payload points to it instead of the data.
*
* @param p the packet to send (p->payload points to the data, e.g. next
protocol header; if dest == IP_HDRINCL, p already includes an IP
header and p->payload points to that IP header)
* @param src the source IP address to send from (if src == IP_ADDR_ANY, the
* IP address of the netif used to send is used as source address)
* @param dest the destination IP address to send the packet to
* @param ttl the TTL value to be set in the IP header
* @param tos the TOS value to be set in the IP header
* @param proto the PROTOCOL to be set in the IP header
* @param netif the netif on which to send this packet
* @return ERR_OK if the packet was sent OK
* ERR_BUF if p doesn't have enough space for IP/LINK headers
* returns errors returned by netif->output
*
* @note ip_id: RFC791 "some host may be able to simply use
* unique identifiers independent of destination"
*/
uint8 ip_output_if(PBUF *p, IP_ADDR *src, IP_ADDR *dest,
uint8 ttl, uint8 tos,
uint8 proto, NETIF *netif)
{
IP_HDR *iphdr;
static uint16 ip_id = 0;
uint8 ret;
/* Should the IP header be generated or is it already included in p? */
if (dest != IP_HDRINCL)
{
uint16 ip_hlen = IP_HLEN;
if (p != NULL)
{
pbuf_header(p, IP_HLEN);
}
iphdr = p->payload;
IPH_TTL_SET(iphdr, ttl);
IPH_PROTO_SET(iphdr, proto);
ip_addr_set(&(iphdr->dest), dest);
IPH_VHLTOS_SET(iphdr, 4, ip_hlen / 4, tos);
IPH_LEN_SET(iphdr, htons(p->len));
IPH_OFFSET_SET(iphdr, 0);
IPH_ID_SET(iphdr, htons(ip_id));
++ip_id;
if (ip_addr_isany(src))
{
ip_addr_set(&(iphdr->src), &(netif->ip_addr));
}
else
{
ip_addr_set(&(iphdr->src), src);
}
IPH_CHKSUM_SET(iphdr, 0);
#if CHECKSUM_GEN_IP
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, ip_hlen)); //wp
#endif
}
else
{
/* IP header already included in p */
iphdr = p->payload;
dest = &(iphdr->dest);
}
//printf("fle--> nefif output\n");
ret = netif->output(netif, p, dest); // etharp_output
return ret;
}
static rt_err_t _low_level_dhcp_send(struct netif *netif,
const void *buffer,
rt_size_t size)
{
struct pbuf *p;
struct eth_hdr *ethhdr;
struct ip_hdr *iphdr;
struct udp_hdr *udphdr;
p = pbuf_alloc(PBUF_LINK,
SIZEOF_ETH_HDR + sizeof(struct ip_hdr)
+ sizeof(struct udp_hdr) + size,
PBUF_RAM);
if (p == RT_NULL) return -RT_ENOMEM;
ethhdr = (struct eth_hdr *)p->payload;
iphdr = (struct ip_hdr *)((char *)ethhdr + SIZEOF_ETH_HDR);
udphdr = (struct udp_hdr *)((char *)iphdr + sizeof(struct ip_hdr));
ETHADDR32_COPY(ðhdr->dest, (struct eth_addr *)ðbroadcast);
ETHADDR16_COPY(ðhdr->src, netif->hwaddr);
ethhdr->type = PP_HTONS(ETHTYPE_IP);
iphdr->src.addr = 0x00000000; /* src: 0.0.0.0 */
iphdr->dest.addr = 0xFFFFFFFF; /* src: 255.255.255.255 */
IPH_VHL_SET(iphdr, 4, IP_HLEN / 4);
IPH_TOS_SET(iphdr, 0x00);
IPH_LEN_SET(iphdr, htons(IP_HLEN + sizeof(struct udp_hdr) + size));
IPH_ID_SET(iphdr, htons(2));
IPH_OFFSET_SET(iphdr, 0);
IPH_TTL_SET(iphdr, 255);
IPH_PROTO_SET(iphdr, IP_PROTO_UDP);
IPH_CHKSUM_SET(iphdr, 0);
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
udphdr->src = htons(DHCP_SERVER_PORT);
udphdr->dest = htons(DHCP_CLIENT_PORT);
udphdr->len = htons(sizeof(struct udp_hdr) + size);
udphdr->chksum = 0;
memcpy((char *)udphdr + sizeof(struct udp_hdr),
buffer, size);
return netif->linkoutput(netif, p);
}
/**
* Fragment an IP datagram if too large for the netif.
*
* Chop the datagram in MTU sized chunks and send them in order
* by using a fixed size static memory buffer (PBUF_REF) or
* point PBUF_REFs into p (depending on IP_FRAG_USES_STATIC_BUF).
*
* @param p ip packet to send
* @param netif the netif on which to send
* @param dest destination ip address to which to send
*
* @return ERR_OK if sent successfully, err_t otherwise
*/
err_t
ip_frag(struct pbuf *p, struct netif *netif, ip_addr_t *dest)
{
struct pbuf *rambuf;
#if IP_FRAG_USES_STATIC_BUF
struct pbuf *header;
#else
#if !LWIP_NETIF_TX_SINGLE_PBUF
struct pbuf *newpbuf;
#endif
struct ip_hdr *original_iphdr;
#endif
struct ip_hdr *iphdr;
u16_t nfb;
u16_t left, cop;
u16_t mtu = netif->mtu;
u16_t ofo, omf;
u16_t last;
u16_t poff = IP_HLEN;
u16_t tmp;
#if !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF
u16_t newpbuflen = 0;
u16_t left_to_copy;
#endif
/* Get a RAM based MTU sized pbuf */
#if IP_FRAG_USES_STATIC_BUF
/* When using a static buffer, we use a PBUF_REF, which we will
* use to reference the packet (without link header).
* Layer and length is irrelevant.
*/
rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
if (rambuf == NULL) {
LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc(PBUF_LINK, 0, PBUF_REF) failed\n"));
return ERR_MEM;
}
rambuf->tot_len = rambuf->len = mtu;
rambuf->payload = LWIP_MEM_ALIGN((void *)buf);
/* Copy the IP header in it */
iphdr = (struct ip_hdr *)rambuf->payload;
SMEMCPY(iphdr, p->payload, IP_HLEN);
#else /* IP_FRAG_USES_STATIC_BUF */
original_iphdr = (struct ip_hdr *)p->payload;
iphdr = original_iphdr;
#endif /* IP_FRAG_USES_STATIC_BUF */
/* Save original offset */
tmp = ntohs(IPH_OFFSET(iphdr));
ofo = tmp & IP_OFFMASK;
omf = tmp & IP_MF;
left = p->tot_len - IP_HLEN;
nfb = (mtu - IP_HLEN) / 8;
while (left) {
last = (left <= mtu - IP_HLEN);
/* Set new offset and MF flag */
tmp = omf | (IP_OFFMASK & (ofo));
if (!last) {
tmp = tmp | IP_MF;
}
/* Fill this fragment */
cop = last ? left : nfb * 8;
#if IP_FRAG_USES_STATIC_BUF
poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff);
#else /* IP_FRAG_USES_STATIC_BUF */
#if LWIP_NETIF_TX_SINGLE_PBUF
rambuf = pbuf_alloc(PBUF_IP, cop, PBUF_RAM);
if (rambuf == NULL) {
return ERR_MEM;
}
LWIP_ASSERT("this needs a pbuf in one piece!",
(rambuf->len == rambuf->tot_len) && (rambuf->next == NULL));
poff += pbuf_copy_partial(p, rambuf->payload, cop, poff);
/* make room for the IP header */
if(pbuf_header(rambuf, IP_HLEN)) {
pbuf_free(rambuf);
return ERR_MEM;
}
/* fill in the IP header */
SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
iphdr = rambuf->payload;
#else /* LWIP_NETIF_TX_SINGLE_PBUF */
/* When not using a static buffer, create a chain of pbufs.
* The first will be a PBUF_RAM holding the link and IP header.
* The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
* but limited to the size of an mtu.
*/
rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM);
if (rambuf == NULL) {
return ERR_MEM;
}
LWIP_ASSERT("this needs a pbuf in one piece!",
(p->len >= (IP_HLEN)));
SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
iphdr = (struct ip_hdr *)rambuf->payload;
/* Can just adjust p directly for needed offset. */
p->payload = (u8_t *)p->payload + poff;
p->len -= poff;
left_to_copy = cop;
while (left_to_copy) {
struct pbuf_custom_ref *pcr;
newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
/* Is this pbuf already empty? */
if (!newpbuflen) {
p = p->next;
continue;
}
pcr = ip_frag_alloc_pbuf_custom_ref();
if (pcr == NULL) {
pbuf_free(rambuf);
return ERR_MEM;
}
/* Mirror this pbuf, although we might not need all of it. */
newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen);
if (newpbuf == NULL) {
ip_frag_free_pbuf_custom_ref(pcr);
pbuf_free(rambuf);
return ERR_MEM;
}
pbuf_ref(p);
pcr->original = p;
pcr->pc.custom_free_function = ipfrag_free_pbuf_custom;
/* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
* so that it is removed when pbuf_dechain is later called on rambuf.
*/
pbuf_cat(rambuf, newpbuf);
left_to_copy -= newpbuflen;
if (left_to_copy) {
p = p->next;
}
}
poff = newpbuflen;
#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
#endif /* IP_FRAG_USES_STATIC_BUF */
/* Correct header */
IPH_OFFSET_SET(iphdr, htons(tmp));
IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
IPH_CHKSUM_SET(iphdr, 0);
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
#if IP_FRAG_USES_STATIC_BUF
if (last) {
pbuf_realloc(rambuf, left + IP_HLEN);
}
/* This part is ugly: we alloc a RAM based pbuf for
* the link level header for each chunk and then
* free it.A PBUF_ROM style pbuf for which pbuf_header
* worked would make things simpler.
*/
header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
if (header != NULL) {
pbuf_chain(header, rambuf);
netif->output(netif, header, dest);
IPFRAG_STATS_INC(ip_frag.xmit);
snmp_inc_ipfragcreates();
pbuf_free(header);
} else {
LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n"));
pbuf_free(rambuf);
return ERR_MEM;
}
#else /* IP_FRAG_USES_STATIC_BUF */
/* No need for separate header pbuf - we allowed room for it in rambuf
* when allocated.
*/
netif->output(netif, rambuf, dest);
IPFRAG_STATS_INC(ip_frag.xmit);
/* Unfortunately we can't reuse rambuf - the hardware may still be
* using the buffer. Instead we free it (and the ensuing chain) and
* recreate it next time round the loop. If we're lucky the hardware
* will have already sent the packet, the free will really free, and
* there will be zero memory penalty.
*/
pbuf_free(rambuf);
#endif /* IP_FRAG_USES_STATIC_BUF */
left -= cop;
ofo += nfb;
}
#if IP_FRAG_USES_STATIC_BUF
pbuf_free(rambuf);
#endif /* IP_FRAG_USES_STATIC_BUF */
snmp_inc_ipfragoks();
return ERR_OK;
}
/**
* Reassembles incoming IP fragments into an IP datagram.
*
* @param p points to a pbuf chain of the fragment
* @return NULL if reassembly is incomplete, ? otherwise
*/
struct pbuf *
ip_reass(struct pbuf *p)
{
struct pbuf *r;
struct ip_hdr *fraghdr;
struct ip_reassdata *ipr;
struct ip_reass_helper *iprh;
u16_t offset, len;
u8_t clen;
struct ip_reassdata *ipr_prev = NULL;
IPFRAG_STATS_INC(ip_frag.recv);
snmp_inc_ipreasmreqds();
fraghdr = (struct ip_hdr*)p->payload;
if ((IPH_HL(fraghdr) * 4) != IP_HLEN) {
LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: IP options currently not supported!\n"));
IPFRAG_STATS_INC(ip_frag.err);
goto nullreturn;
}
offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
/* Check if we are allowed to enqueue more datagrams. */
clen = pbuf_clen(p);
if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
#if IP_REASS_FREE_OLDEST
if (!ip_reass_remove_oldest_datagram(fraghdr, clen) ||
((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
#endif /* IP_REASS_FREE_OLDEST */
{
/* No datagram could be freed and still too many pbufs enqueued */
LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n",
ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS));
IPFRAG_STATS_INC(ip_frag.memerr);
/* @todo: send ICMP time exceeded here? */
/* drop this pbuf */
goto nullreturn;
}
}
/* Look for the datagram the fragment belongs to in the current datagram queue,
* remembering the previous in the queue for later dequeueing. */
for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
/* Check if the incoming fragment matches the one currently present
in the reassembly buffer. If so, we proceed with copying the
fragment into the buffer. */
if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
ntohs(IPH_ID(fraghdr))));
IPFRAG_STATS_INC(ip_frag.cachehit);
break;
}
ipr_prev = ipr;
}
if (ipr == NULL) {
/* Enqueue a new datagram into the datagram queue */
ipr = ip_reass_enqueue_new_datagram(fraghdr, clen);
/* Bail if unable to enqueue */
if(ipr == NULL) {
goto nullreturn;
}
} else {
if (((ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) &&
((ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) {
/* ipr->iphdr is not the header from the first fragment, but fraghdr is
* -> copy fraghdr into ipr->iphdr since we want to have the header
* of the first fragment (for ICMP time exceeded and later, for copying
* all options, if supported)*/
SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN);
}
}
/* Track the current number of pbufs current 'in-flight', in order to limit
the number of fragments that may be enqueued at any one time */
ip_reass_pbufcount += clen;
/* At this point, we have either created a new entry or pointing
* to an existing one */
/* check for 'no more fragments', and update queue entry*/
if ((IPH_OFFSET(fraghdr) & PP_NTOHS(IP_MF)) == 0) {
ipr->flags |= IP_REASS_FLAG_LASTFRAG;
ipr->datagram_len = offset + len;
LWIP_DEBUGF(IP_REASS_DEBUG,
("ip_reass: last fragment seen, total len %"S16_F"\n",
ipr->datagram_len));
}
/* find the right place to insert this pbuf */
/* @todo: trim pbufs if fragments are overlapping */
if (ip_reass_chain_frag_into_datagram_and_validate(ipr, p)) {
/* the totally last fragment (flag more fragments = 0) was received at least
* once AND all fragments are received */
ipr->datagram_len += IP_HLEN;
/* save the second pbuf before copying the header over the pointer */
r = ((struct ip_reass_helper*)ipr->p->payload)->next_pbuf;
/* copy the original ip header back to the first pbuf */
fraghdr = (struct ip_hdr*)(ipr->p->payload);
SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN);
IPH_LEN_SET(fraghdr, htons(ipr->datagram_len));
IPH_OFFSET_SET(fraghdr, 0);
IPH_CHKSUM_SET(fraghdr, 0);
/* @todo: do we need to set calculate the correct checksum? */
IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN));
p = ipr->p;
/* chain together the pbufs contained within the reass_data list. */
while(r != NULL) {
iprh = (struct ip_reass_helper*)r->payload;
/* hide the ip header for every succeding fragment */
pbuf_header(r, -IP_HLEN);
pbuf_cat(p, r);
r = iprh->next_pbuf;
}
/* release the sources allocate for the fragment queue entry */
ip_reass_dequeue_datagram(ipr, ipr_prev);
/* and adjust the number of pbufs currently queued for reassembly. */
ip_reass_pbufcount -= pbuf_clen(p);
/* Return the pbuf chain */
return p;
}
/* the datagram is not (yet?) reassembled completely */
LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount));
return NULL;
nullreturn:
LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: nullreturn\n"));
IPFRAG_STATS_INC(ip_frag.drop);
pbuf_free(p);
return NULL;
}
/**
* This function is called by the network interface device driver when
* an IP packet is received. The function does the basic checks of the
* IP header such as packet size being at least larger than the header
* size etc. If the packet was not destined for us, the packet is
* forwarded (using ip_forward). The IP checksum is always checked.
*
* Finally, the packet is sent to the upper layer protocol input function.
*
* @param p the received IP packet (p->payload points to IP header)
* @param inp the netif on which this packet was received
* @return ERR_OK if the packet was processed (could return ERR_* if it wasn't
* processed, but currently always returns ERR_OK)
*/
err_t
ip_input(struct pbuf *p, struct netif *inp)
{
struct ip_hdr *iphdr;
struct netif *netif;
u16_t iphdr_hlen;
u16_t iphdr_len;
#if LWIP_DHCP
int check_ip_src=1;
#endif /* LWIP_DHCP */
IP_STATS_INC(ip.recv);
snmp_inc_ipinreceives();
/* identify the IP header */
iphdr = p->payload;
if (IPH_V(iphdr) != 4) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IP packet dropped due to bad version number %"U16_F"\n", IPH_V(iphdr)));
ip_debug_print(p);
pbuf_free(p);
IP_STATS_INC(ip.err);
IP_STATS_INC(ip.drop);
snmp_inc_ipinhdrerrors();
return ERR_OK;
}
/* obtain IP header length in number of 32-bit words */
iphdr_hlen = IPH_HL(iphdr);
/* calculate IP header length in bytes */
iphdr_hlen *= 4;
/* obtain ip length in bytes */
iphdr_len = ntohs(IPH_LEN(iphdr));
/* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */
if ((iphdr_hlen > p->len) || (iphdr_len > p->tot_len)) {
if (iphdr_hlen > p->len) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("IP header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet dropped.\n",
iphdr_hlen, p->len));
}
if (iphdr_len > p->tot_len) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("IP (len %"U16_F") is longer than pbuf (len %"U16_F"), IP packet dropped.\n",
iphdr_len, p->tot_len));
}
/* free (drop) packet pbufs */
pbuf_free(p);
IP_STATS_INC(ip.lenerr);
IP_STATS_INC(ip.drop);
snmp_inc_ipindiscards();
return ERR_OK;
}
/* verify checksum */
#if CHECKSUM_CHECK_IP
if (inet_chksum(iphdr, iphdr_hlen) != 0) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("Checksum (0x%"X16_F") failed, IP packet dropped.\n", inet_chksum(iphdr, iphdr_hlen)));
ip_debug_print(p);
pbuf_free(p);
IP_STATS_INC(ip.chkerr);
IP_STATS_INC(ip.drop);
snmp_inc_ipinhdrerrors();
return ERR_OK;
}
#endif
/* Trim pbuf. This should have been done at the netif layer,
* but we'll do it anyway just to be sure that its done. */
pbuf_realloc(p, iphdr_len);
/* match packet against an interface, i.e. is this packet for us? */
#if LWIP_IGMP
if (ip_addr_ismulticast(&(iphdr->dest))) {
if ((inp->flags & NETIF_FLAG_IGMP) && (igmp_lookfor_group(inp, &(iphdr->dest)))) {
netif = inp;
} else {
netif = NULL;
}
} else
#endif /* LWIP_IGMP */
{
/* start trying with inp. if that's not acceptable, start walking the
list of configured netifs.
'first' is used as a boolean to mark whether we started walking the list */
int first = 1;
netif = inp;
do {
LWIP_DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest 0x%"X32_F" netif->ip_addr 0x%"X32_F" (0x%"X32_F", 0x%"X32_F", 0x%"X32_F")\n",
iphdr->dest.addr, netif->ip_addr.addr,
iphdr->dest.addr & netif->netmask.addr,
netif->ip_addr.addr & netif->netmask.addr,
iphdr->dest.addr & ~(netif->netmask.addr)));
/* interface is up and configured? */
if ((netif_is_up(netif)) && (!ip_addr_isany(&(netif->ip_addr)))) {
/* unicast to this interface address? */
if (ip_addr_cmp(&(iphdr->dest), &(netif->ip_addr)) ||
/* or broadcast on this interface network address? */
ip_addr_isbroadcast(&(iphdr->dest), netif)) {
LWIP_DEBUGF(IP_DEBUG, ("ip_input: packet accepted on interface %c%c\n",
netif->name[0], netif->name[1]));
/* break out of for loop */
break;
}
}
if (first) {
first = 0;
netif = netif_list;
} else {
netif = netif->next;
}
if (netif == inp) {
netif = netif->next;
}
} while(netif != NULL);
}
#if LWIP_DHCP
/* Pass DHCP messages regardless of destination address. DHCP traffic is addressed
* using link layer addressing (such as Ethernet MAC) so we must not filter on IP.
* According to RFC 1542 section 3.1.1, referred by RFC 2131).
*/
if (netif == NULL) {
/* remote port is DHCP server? */
if (IPH_PROTO(iphdr) == IP_PROTO_UDP) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip_input: UDP packet to DHCP client port %"U16_F"\n",
ntohs(((struct udp_hdr *)((u8_t *)iphdr + iphdr_hlen))->dest)));
if (ntohs(((struct udp_hdr *)((u8_t *)iphdr + iphdr_hlen))->dest) == DHCP_CLIENT_PORT) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip_input: DHCP packet accepted.\n"));
netif = inp;
check_ip_src = 0;
}
}
}
#endif /* LWIP_DHCP */
/* broadcast or multicast packet source address? Compliant with RFC 1122: 3.2.1.3 */
#if LWIP_DHCP
/* DHCP servers need 0.0.0.0 to be allowed as source address (RFC 1.1.2.2: 3.2.1.3/a) */
if (check_ip_src && (iphdr->src.addr != 0))
#endif /* LWIP_DHCP */
{ if ((ip_addr_isbroadcast(&(iphdr->src), inp)) ||
(ip_addr_ismulticast(&(iphdr->src)))) {
/* packet source is not valid */
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("ip_input: packet source is not valid.\n"));
/* free (drop) packet pbufs */
pbuf_free(p);
IP_STATS_INC(ip.drop);
snmp_inc_ipinaddrerrors();
snmp_inc_ipindiscards();
return ERR_OK;
}
}
/* packet not for us? */
if (netif == NULL) {
/* packet not for us, route or discard */
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip_input: packet not for us.\n"));
#if IP_FORWARD
/* non-broadcast packet? */
if (!ip_addr_isbroadcast(&(iphdr->dest), inp)) {
/* try to forward IP packet on (other) interfaces */
ip_forward(p, iphdr, inp);
} else
#endif /* IP_FORWARD */
{
snmp_inc_ipinaddrerrors();
snmp_inc_ipindiscards();
}
pbuf_free(p);
return ERR_OK;
}
/* packet consists of multiple fragments? */
if ((IPH_OFFSET(iphdr) & htons(IP_OFFMASK | IP_MF)) != 0) {
#if IP_REASSEMBLY /* packet fragment reassembly code present? */
LWIP_DEBUGF(IP_DEBUG, ("IP packet is a fragment (id=0x%04"X16_F" tot_len=%"U16_F" len=%"U16_F" MF=%"U16_F" offset=%"U16_F"), calling ip_reass()\n",
ntohs(IPH_ID(iphdr)), p->tot_len, ntohs(IPH_LEN(iphdr)), !!(IPH_OFFSET(iphdr) & htons(IP_MF)), (ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)*8));
/* reassemble the packet*/
p = ip_reass(p);
/* packet not fully reassembled yet? */
if (p == NULL) {
return ERR_OK;
}
iphdr = p->payload;
#else /* IP_REASSEMBLY == 0, no packet fragment reassembly code present */
pbuf_free(p);
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since it was fragmented (0x%"X16_F") (while IP_REASSEMBLY == 0).\n",
ntohs(IPH_OFFSET(iphdr))));
IP_STATS_INC(ip.opterr);
IP_STATS_INC(ip.drop);
/* unsupported protocol feature */
snmp_inc_ipinunknownprotos();
return ERR_OK;
#endif /* IP_REASSEMBLY */
}
#if IP_OPTIONS_ALLOWED == 0 /* no support for IP options in the IP header? */
#if LWIP_IGMP
/* there is an extra "router alert" option in IGMP messages which we allow for but do not police */
if((iphdr_hlen > IP_HLEN && (IPH_PROTO(iphdr) != IP_PROTO_IGMP)) {
#else
if (iphdr_hlen > IP_HLEN) {
#endif /* LWIP_IGMP */
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since there were IP options (while IP_OPTIONS_ALLOWED == 0).\n"));
pbuf_free(p);
IP_STATS_INC(ip.opterr);
IP_STATS_INC(ip.drop);
/* unsupported protocol feature */
snmp_inc_ipinunknownprotos();
return ERR_OK;
}
#endif /* IP_OPTIONS_ALLOWED == 0 */
/* send to upper layers */
LWIP_DEBUGF(IP_DEBUG, ("ip_input: \n"));
ip_debug_print(p);
LWIP_DEBUGF(IP_DEBUG, ("ip_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len));
current_netif = inp;
current_header = iphdr;
#if LWIP_RAW
/* raw input did not eat the packet? */
if (raw_input(p, inp) == 0)
#endif /* LWIP_RAW */
{
switch (IPH_PROTO(iphdr)) {
#if LWIP_UDP
case IP_PROTO_UDP:
#if LWIP_UDPLITE
case IP_PROTO_UDPLITE:
#endif /* LWIP_UDPLITE */
snmp_inc_ipindelivers();
udp_input(p, inp);
break;
#endif /* LWIP_UDP */
#if LWIP_TCP
case IP_PROTO_TCP:
snmp_inc_ipindelivers();
tcp_input(p, inp);
break;
#endif /* LWIP_TCP */
#if LWIP_ICMP
case IP_PROTO_ICMP:
snmp_inc_ipindelivers();
icmp_input(p, inp);
break;
#endif /* LWIP_ICMP */
#if LWIP_IGMP
case IP_PROTO_IGMP:
igmp_input(p,inp,&(iphdr->dest));
break;
#endif /* LWIP_IGMP */
default:
#if LWIP_ICMP
/* send ICMP destination protocol unreachable unless is was a broadcast */
if (!ip_addr_isbroadcast(&(iphdr->dest), inp) &&
!ip_addr_ismulticast(&(iphdr->dest))) {
p->payload = iphdr;
icmp_dest_unreach(p, ICMP_DUR_PROTO);
}
#endif /* LWIP_ICMP */
pbuf_free(p);
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Unsupported transport protocol %"U16_F"\n", IPH_PROTO(iphdr)));
IP_STATS_INC(ip.proterr);
IP_STATS_INC(ip.drop);
snmp_inc_ipinunknownprotos();
}
}
current_netif = NULL;
current_header = NULL;
return ERR_OK;
}
/**
* Sends an IP packet on a network interface. This function constructs
* the IP header and calculates the IP header checksum. If the source
* IP address is NULL, the IP address of the outgoing network
* interface is filled in as source address.
* If the destination IP address is IP_HDRINCL, p is assumed to already
* include an IP header and p->payload points to it instead of the data.
*
* @param p the packet to send (p->payload points to the data, e.g. next
protocol header; if dest == IP_HDRINCL, p already includes an IP
header and p->payload points to that IP header)
* @param src the source IP address to send from (if src == IP_ADDR_ANY, the
* IP address of the netif used to send is used as source address)
* @param dest the destination IP address to send the packet to
* @param ttl the TTL value to be set in the IP header
* @param tos the TOS value to be set in the IP header
* @param proto the PROTOCOL to be set in the IP header
* @param netif the netif on which to send this packet
* @return ERR_OK if the packet was sent OK
* ERR_BUF if p doesn't have enough space for IP/LINK headers
* returns errors returned by netif->output
*
* @note ip_id: RFC791 "some host may be able to simply use
* unique identifiers independent of destination"
*/
err_t
ip_output_if(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
u8_t ttl, u8_t tos,
u8_t proto, struct netif *netif)
{
#if IP_OPTIONS_SEND
return ip_output_if_opt(p, src, dest, ttl, tos, proto, netif, NULL, 0);
}
/**
* Same as ip_output_if() but with the possibility to include IP options:
*
* @ param ip_options pointer to the IP options, copied into the IP header
* @ param optlen length of ip_options
*/
err_t ip_output_if_opt(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
u16_t optlen)
{
#endif /* IP_OPTIONS_SEND */
struct ip_hdr *iphdr;
static u16_t ip_id = 0;
snmp_inc_ipoutrequests();
/* Should the IP header be generated or is it already included in p? */
if (dest != IP_HDRINCL) {
u16_t ip_hlen = IP_HLEN;
#if IP_OPTIONS_SEND
u16_t optlen_aligned = 0;
if (optlen != 0) {
/* round up to a multiple of 4 */
optlen_aligned = ((optlen + 3) & ~3);
ip_hlen += optlen_aligned;
/* First write in the IP options */
if (pbuf_header(p, optlen_aligned)) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip_output_if_opt: not enough room for IP options in pbuf\n"));
IP_STATS_INC(ip.err);
snmp_inc_ipoutdiscards();
return ERR_BUF;
}
MEMCPY(p->payload, ip_options, optlen);
if (optlen < optlen_aligned) {
/* zero the remaining bytes */
memset(((char*)p->payload) + optlen, 0, optlen_aligned - optlen);
}
}
#endif /* IP_OPTIONS_SEND */
/* generate IP header */
if (pbuf_header(p, IP_HLEN)) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip_output: not enough room for IP header in pbuf\n"));
IP_STATS_INC(ip.err);
snmp_inc_ipoutdiscards();
return ERR_BUF;
}
iphdr = p->payload;
LWIP_ASSERT("check that first pbuf can hold struct ip_hdr",
(p->len >= sizeof(struct ip_hdr)));
IPH_TTL_SET(iphdr, ttl);
IPH_PROTO_SET(iphdr, proto);
ip_addr_set(&(iphdr->dest), dest);
IPH_VHLTOS_SET(iphdr, 4, ip_hlen / 4, tos);
IPH_LEN_SET(iphdr, htons(p->tot_len));
IPH_OFFSET_SET(iphdr, 0);
IPH_ID_SET(iphdr, htons(ip_id));
++ip_id;
if (ip_addr_isany(src)) {
ip_addr_set(&(iphdr->src), &(netif->ip_addr));
} else {
ip_addr_set(&(iphdr->src), src);
}
IPH_CHKSUM_SET(iphdr, 0);
#if CHECKSUM_GEN_IP
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, ip_hlen));
#endif
} else {
/* IP header already included in p */
iphdr = p->payload;
dest = &(iphdr->dest);
}
IP_STATS_INC(ip.xmit);
LWIP_DEBUGF(IP_DEBUG, ("ip_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], netif->num));
ip_debug_print(p);
#if ENABLE_LOOPBACK
if (ip_addr_cmp(dest, &netif->ip_addr)) {
/* Packet to self, enqueue it for loopback */
LWIP_DEBUGF(IP_DEBUG, ("netif_loop_output()"));
return netif_loop_output(netif, p, dest);
}
#endif /* ENABLE_LOOPBACK */
#if IP_FRAG
/* don't fragment if interface has mtu set to 0 [loopif] */
if (netif->mtu && (p->tot_len > netif->mtu)) {
return ip_frag(p,netif,dest);
}
#endif
LWIP_DEBUGF(IP_DEBUG, ("netif->output()"));
return netif->output(netif, p, dest);
}
/**
* Simple interface to ip_output_if. It finds the outgoing network
* interface and calls upon ip_output_if to do the actual work.
*
* @param p the packet to send (p->payload points to the data, e.g. next
protocol header; if dest == IP_HDRINCL, p already includes an IP
header and p->payload points to that IP header)
* @param src the source IP address to send from (if src == IP_ADDR_ANY, the
* IP address of the netif used to send is used as source address)
* @param dest the destination IP address to send the packet to
* @param ttl the TTL value to be set in the IP header
* @param tos the TOS value to be set in the IP header
* @param proto the PROTOCOL to be set in the IP header
*
* @return ERR_RTE if no route is found
* see ip_output_if() for more return values
*/
err_t
ip_output(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
u8_t ttl, u8_t tos, u8_t proto)
{
struct netif *netif;
if ((netif = ip_route(dest)) == NULL) {
LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to 0x%"X32_F"\n", dest->addr));
IP_STATS_INC(ip.rterr);
return ERR_RTE;
}
return ip_output_if(p, src, dest, ttl, tos, proto, netif);
}
#if LWIP_NETIF_HWADDRHINT
/** Like ip_output, but takes and addr_hint pointer that is passed on to netif->addr_hint
* before calling ip_output_if.
*
* @param p the packet to send (p->payload points to the data, e.g. next
protocol header; if dest == IP_HDRINCL, p already includes an IP
header and p->payload points to that IP header)
* @param src the source IP address to send from (if src == IP_ADDR_ANY, the
* IP address of the netif used to send is used as source address)
* @param dest the destination IP address to send the packet to
* @param ttl the TTL value to be set in the IP header
* @param tos the TOS value to be set in the IP header
* @param proto the PROTOCOL to be set in the IP header
* @param addr_hint address hint pointer set to netif->addr_hint before
* calling ip_output_if()
*
* @return ERR_RTE if no route is found
* see ip_output_if() for more return values
*/
err_t
ip_output_hinted(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
u8_t ttl, u8_t tos, u8_t proto, u8_t *addr_hint)
{
struct netif *netif;
err_t err;
if ((netif = ip_route(dest)) == NULL) {
LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to 0x%"X32_F"\n", dest->addr));
IP_STATS_INC(ip.rterr);
return ERR_RTE;
}
netif->addr_hint = addr_hint;
err = ip_output_if(p, src, dest, ttl, tos, proto, netif);
netif->addr_hint = NULL;
return err;
}
#endif /* LWIP_NETIF_HWADDRHINT*/
#if IP_DEBUG
/* Print an IP header by using LWIP_DEBUGF
* @param p an IP packet, p->payload pointing to the IP header
*/
void
ip_debug_print(struct pbuf *p)
{
struct ip_hdr *iphdr = p->payload;
u8_t *payload;
payload = (u8_t *)iphdr + IP_HLEN;
LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));
LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |%2"S16_F" | 0x%02"X16_F" | %5"U16_F" | (v, hl, tos, len)\n",
IPH_V(iphdr),
IPH_HL(iphdr),
IPH_TOS(iphdr),
ntohs(IPH_LEN(iphdr))));
LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(IP_DEBUG, ("| %5"U16_F" |%"U16_F"%"U16_F"%"U16_F"| %4"U16_F" | (id, flags, offset)\n",
ntohs(IPH_ID(iphdr)),
ntohs(IPH_OFFSET(iphdr)) >> 15 & 1,
ntohs(IPH_OFFSET(iphdr)) >> 14 & 1,
ntohs(IPH_OFFSET(iphdr)) >> 13 & 1,
ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK));
LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | 0x%04"X16_F" | (ttl, proto, chksum)\n",
IPH_TTL(iphdr),
IPH_PROTO(iphdr),
ntohs(IPH_CHKSUM(iphdr))));
LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (src)\n",
ip4_addr1(&iphdr->src),
ip4_addr2(&iphdr->src),
ip4_addr3(&iphdr->src),
ip4_addr4(&iphdr->src)));
LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (dest)\n",
ip4_addr1(&iphdr->dest),
ip4_addr2(&iphdr->dest),
ip4_addr3(&iphdr->dest),
ip4_addr4(&iphdr->dest)));
LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
}
/**
* Fragment an IP datagram if too large for the netif.
*
* Chop the datagram in MTU sized chunks and send them in order
* by using a fixed size static memory buffer (PBUF_ROM)
*/
err_t
ip_frag(struct pbuf *p, struct netif *netif, struct ip_addr *dest)
{
struct pbuf *rambuf;
struct pbuf *header;
struct ip_hdr *iphdr;
u16_t nfb = 0;
u16_t left, cop;
u16_t mtu = netif->mtu;
u16_t ofo, omf;
u16_t last;
u16_t poff = IP_HLEN;
u16_t tmp;
/* Get a RAM based MTU sized pbuf */
rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
if (rambuf == NULL) {
return ERR_MEM;
}
rambuf->tot_len = rambuf->len = mtu;
rambuf->payload = MEM_ALIGN((void *)buf);
/* Copy the IP header in it */
iphdr = rambuf->payload;
memcpy(iphdr, p->payload, IP_HLEN);
/* Save original offset */
tmp = ntohs(IPH_OFFSET(iphdr));
ofo = tmp & IP_OFFMASK;
omf = tmp & IP_MF;
left = p->tot_len - IP_HLEN;
while (left) {
last = (left <= mtu - IP_HLEN);
/* Set new offset and MF flag */
ofo += nfb;
tmp = omf | (IP_OFFMASK & (ofo));
if (!last)
tmp = tmp | IP_MF;
IPH_OFFSET_SET(iphdr, htons(tmp));
/* Fill this fragment */
nfb = (mtu - IP_HLEN) / 8;
cop = last ? left : nfb * 8;
p = copy_from_pbuf(p, &poff, (u8_t *) iphdr + IP_HLEN, cop);
/* Correct header */
IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
IPH_CHKSUM_SET(iphdr, 0);
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
if (last)
pbuf_realloc(rambuf, left + IP_HLEN);
/* This part is ugly: we alloc a RAM based pbuf for
* the link level header for each chunk and then
* free it.A PBUF_ROM style pbuf for which pbuf_header
* worked would make things simpler.
*/
header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
if (header != NULL) {
pbuf_chain(header, rambuf);
netif->output(netif, header, dest);
IPFRAG_STATS_INC(ip_frag.xmit);
pbuf_free(header);
} else {
pbuf_free(rambuf);
return ERR_MEM;
}
left -= cop;
}
pbuf_free(rambuf);
return ERR_OK;
}
/**
* Reassembles incoming IP fragments into an IP datagram.
*
* @param p points to a pbuf chain of the fragment
* @return NULL if reassembly is incomplete, ? otherwise
*/
struct pbuf *
ip_reass(struct pbuf *p)
{
struct pbuf *q;
struct ip_hdr *fraghdr, *iphdr;
u16_t offset, len;
u16_t i;
IPFRAG_STATS_INC(ip_frag.recv);
iphdr = (struct ip_hdr *) ip_reassbuf;
fraghdr = (struct ip_hdr *) p->payload;
/* If ip_reasstmr is zero, no packet is present in the buffer, so we
write the IP header of the fragment into the reassembly
buffer. The timer is updated with the maximum age. */
if (ip_reasstmr == 0) {
LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: new packet\n"));
memcpy(iphdr, fraghdr, IP_HLEN);
ip_reasstmr = IP_REASS_MAXAGE;
ip_reassflags = 0;
/* Clear the bitmap. */
memset(ip_reassbitmap, 0, sizeof(ip_reassbitmap));
}
/* Check if the incoming fragment matches the one currently present
in the reasembly buffer. If so, we proceed with copying the
fragment into the buffer. */
if (ip_addr_cmp(&iphdr->src, &fraghdr->src) &&
ip_addr_cmp(&iphdr->dest, &fraghdr->dest) &&
IPH_ID(iphdr) == IPH_ID(fraghdr)) {
LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
ntohs(IPH_ID(fraghdr))));
IPFRAG_STATS_INC(ip_frag.cachehit);
/* Find out the offset in the reassembly buffer where we should
copy the fragment. */
len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
/* If the offset or the offset + fragment length overflows the
reassembly buffer, we discard the entire packet. */
if (offset > IP_REASS_BUFSIZE || offset + len > IP_REASS_BUFSIZE) {
LWIP_DEBUGF(IP_REASS_DEBUG,
("ip_reass: fragment outside of buffer (%"S16_F":%"S16_F"/%"S16_F").\n", offset,
offset + len, IP_REASS_BUFSIZE));
ip_reasstmr = 0;
goto nullreturn;
}
/* Copy the fragment into the reassembly buffer, at the right
offset. */
LWIP_DEBUGF(IP_REASS_DEBUG,
("ip_reass: copying with offset %"S16_F" into %"S16_F":%"S16_F"\n", offset,
IP_HLEN + offset, IP_HLEN + offset + len));
i = IPH_HL(fraghdr) * 4;
copy_from_pbuf(p, &i, &ip_reassbuf[IP_HLEN + offset], len);
/* Update the bitmap. */
if (offset / (8 * 8) == (offset + len) / (8 * 8)) {
LWIP_DEBUGF(IP_REASS_DEBUG,
("ip_reass: updating single byte in bitmap.\n"));
/* If the two endpoints are in the same byte, we only update that byte. */
LWIP_ASSERT("offset / (8 * 8) < sizeof(ip_reassbitmap)",
offset / (8 * 8) < sizeof(ip_reassbitmap));
ip_reassbitmap[offset / (8 * 8)] |=
bitmap_bits[(offset / 8) & 7] &
~bitmap_bits[((offset + len) / 8) & 7];
} else {
/* If the two endpoints are in different bytes, we update the
bytes in the endpoints and fill the stuff inbetween with
0xff. */
LWIP_ASSERT("offset / (8 * 8) < sizeof(ip_reassbitmap)",
offset / (8 * 8) < sizeof(ip_reassbitmap));
ip_reassbitmap[offset / (8 * 8)] |= bitmap_bits[(offset / 8) & 7];
LWIP_DEBUGF(IP_REASS_DEBUG,
("ip_reass: updating many bytes in bitmap (%"S16_F":%"S16_F").\n",
1 + offset / (8 * 8), (offset + len) / (8 * 8)));
for (i = 1 + offset / (8 * 8); i < (offset + len) / (8 * 8); ++i) {
ip_reassbitmap[i] = 0xff;
}
LWIP_ASSERT("(offset + len) / (8 * 8) < sizeof(ip_reassbitmap)",
(offset + len) / (8 * 8) < sizeof(ip_reassbitmap));
ip_reassbitmap[(offset + len) / (8 * 8)] |=
~bitmap_bits[((offset + len) / 8) & 7];
}
/* If this fragment has the More Fragments flag set to zero, we
know that this is the last fragment, so we can calculate the
size of the entire packet. We also set the
IP_REASS_FLAG_LASTFRAG flag to indicate that we have received
the final fragment. */
if ((ntohs(IPH_OFFSET(fraghdr)) & IP_MF) == 0) {
ip_reassflags |= IP_REASS_FLAG_LASTFRAG;
ip_reasslen = offset + len;
LWIP_DEBUGF(IP_REASS_DEBUG,
("ip_reass: last fragment seen, total len %"S16_F"\n",
ip_reasslen));
}
/* Finally, we check if we have a full packet in the buffer. We do
this by checking if we have the last fragment and if all bits
in the bitmap are set. */
if (ip_reassflags & IP_REASS_FLAG_LASTFRAG) {
/* Check all bytes up to and including all but the last byte in
the bitmap. */
LWIP_ASSERT("ip_reasslen / (8 * 8) - 1 < sizeof(ip_reassbitmap)",
ip_reasslen / (8 * 8) - 1 < sizeof(ip_reassbitmap));
for (i = 0; i < ip_reasslen / (8 * 8) - 1; ++i) {
if (ip_reassbitmap[i] != 0xff) {
LWIP_DEBUGF(IP_REASS_DEBUG,
("ip_reass: last fragment seen, bitmap %"S16_F"/%"S16_F" failed (%"X16_F")\n",
i, ip_reasslen / (8 * 8) - 1, ip_reassbitmap[i]));
goto nullreturn;
}
}
/* Check the last byte in the bitmap. It should contain just the
right amount of bits. */
LWIP_ASSERT("ip_reasslen / (8 * 8) < sizeof(ip_reassbitmap)",
ip_reasslen / (8 * 8) < sizeof(ip_reassbitmap));
if (ip_reassbitmap[ip_reasslen / (8 * 8)] !=
(u8_t) ~ bitmap_bits[ip_reasslen / 8 & 7]) {
LWIP_DEBUGF(IP_REASS_DEBUG,
("ip_reass: last fragment seen, bitmap %"S16_F" didn't contain %"X16_F" (%"X16_F")\n",
ip_reasslen / (8 * 8), ~bitmap_bits[ip_reasslen / 8 & 7],
ip_reassbitmap[ip_reasslen / (8 * 8)]));
goto nullreturn;
}
/* Pretend to be a "normal" (i.e., not fragmented) IP packet
from now on. */
ip_reasslen += IP_HLEN;
IPH_LEN_SET(iphdr, htons(ip_reasslen));
IPH_OFFSET_SET(iphdr, 0);
IPH_CHKSUM_SET(iphdr, 0);
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
/* If we have come this far, we have a full packet in the
buffer, so we allocate a pbuf and copy the packet into it. We
also reset the timer. */
ip_reasstmr = 0;
pbuf_free(p);
p = pbuf_alloc(PBUF_LINK, ip_reasslen, PBUF_POOL);
if (p != NULL) {
i = 0;
for (q = p; q != NULL; q = q->next) {
/* Copy enough bytes to fill this pbuf in the chain. The
available data in the pbuf is given by the q->len variable. */
LWIP_DEBUGF(IP_REASS_DEBUG,
("ip_reass: memcpy from %p (%"S16_F") to %p, %"S16_F" bytes\n",
(void *)&ip_reassbuf[i], i, q->payload,
q->len > ip_reasslen - i ? ip_reasslen - i : q->len));
memcpy(q->payload, &ip_reassbuf[i],
q->len > ip_reasslen - i ? ip_reasslen - i : q->len);
i += q->len;
}
IPFRAG_STATS_INC(ip_frag.fw);
} else {
IPFRAG_STATS_INC(ip_frag.memerr);
}
LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: p %p\n", (void*)p));
return p;
}
}
nullreturn:
IPFRAG_STATS_INC(ip_frag.drop);
pbuf_free(p);
return NULL;
}
err_t
ip_output_if(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
u8_t ttl, u8_t tos,
u8_t proto, struct netif *netif)
{
struct ip_hdr *iphdr;
static u16_t ip_id = 0;
snmp_inc_ipoutrequests();
if (dest != IP_HDRINCL) {
if (pbuf_header(p, IP_HLEN)) {
LWIP_DEBUGF(IP_DEBUG | 2, ("ip_output: not enough room for IP header in pbuf\n"));
IP_STATS_INC(ip.err);
snmp_inc_ipoutdiscards();
return ERR_BUF;
}
iphdr = p->payload;
IPH_TTL_SET(iphdr, ttl);
IPH_PROTO_SET(iphdr, proto);
ip_addr_set(&(iphdr->dest), dest);
IPH_VHLTOS_SET(iphdr, 4, IP_HLEN / 4, tos);
IPH_LEN_SET(iphdr, htons(p->tot_len));
IPH_OFFSET_SET(iphdr, htons(IP_DF));
IPH_ID_SET(iphdr, htons(ip_id));
++ip_id;
if (ip_addr_isany(src)) {
ip_addr_set(&(iphdr->src), &(netif->ip_addr));
} else {
ip_addr_set(&(iphdr->src), src);
}
IPH_CHKSUM_SET(iphdr, 0);
#if CHECKSUM_GEN_IP
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
#endif
} else {
iphdr = p->payload;
dest = &(iphdr->dest);
}
#if IP_FRAG
/* don't fragment if interface has mtu set to 0 [loopif] */
if (netif->mtu && (p->tot_len > netif->mtu))
return ip_frag(p,netif,dest);
#endif
IP_STATS_INC(ip.xmit);
LWIP_DEBUGF(IP_DEBUG, ("ip_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], netif->num));
ip_debug_print(p);
LWIP_DEBUGF(IP_DEBUG, ("netif->output()"));
return netif->output(netif, p, dest);
}
bool generate_response_ICMP_packet(packet_info_t *pi, int type, int code) {
byte *old_packet = malloc_or_die(pi->len-IPV4_HEADER_OFFSET); //Free'd (below).
memcpy(old_packet, pi->packet+IPV4_HEADER_OFFSET, pi->len-IPV4_HEADER_OFFSET);
struct ip_hdr *old_iphdr = (void *)old_packet;
free(pi->packet);
pi->len = IPV4_HEADER_OFFSET+IPV4_HEADER_LENGTH+36;//14 for Ethernet header, 20 for IPv4 header and 36 for ICMP time exceeded packet.
pi->packet = malloc_or_die((pi->len)*sizeof(byte)); //Free'd (before).
struct eth_hdr *ethhdr = (void *)pi->packet;
ETH_DEST_SET(ethhdr, make_mac_addr(0, 0, 0, 0, 0, 0));
ETH_SRC_SET(ethhdr, make_mac_addr(0, 0, 0, 0, 0, 0));
ETH_TYPE_SET(ethhdr, 0);
struct ip_hdr *iphdr = (void *)pi->packet+IPV4_HEADER_OFFSET;
IPH_VHLTOS_SET(iphdr, 4, 5, 0); //Set version and IHL.
IPH_LEN_SET(iphdr, htons(pi->len-IPV4_HEADER_OFFSET));
IPH_ID_SET(iphdr, 0);
IPH_OFFSET_SET(iphdr, 0);
IPH_TTL_SET(iphdr, 32);
IPH_PROTO_SET(iphdr, 1);
addr_ip_t dest = IPH_SRC(old_iphdr);
addr_ip_t target = sr_integ_findnextip(dest);
interface_t *source_intf = sr_integ_findsrcintf(target);
if (source_intf == NULL) {
char ip_str[STRLEN_IP], target_str[STRLEN_IP];
ip_to_string(ip_str, dest);
ip_to_string(target_str, target);
debug_println("No route to source %s with target %s, dropping packet!", ip_str, target_str);
free(old_packet);
return 1;
}
addr_ip_t source = source_intf->ip;
char dest_str[15];
ip_to_string(dest_str, dest);
char source_str[15];
ip_to_string(source_str, source);
debug_println("dest=%s, source=%s", dest_str, source_str);
memcpy(&IPH_SRC(iphdr), &source, 6);
memcpy(&IPH_DEST(iphdr), &dest, 6);
byte *icmp_packet = pi->packet+IPV4_HEADER_OFFSET+IPV4_HEADER_LENGTH;
struct icmp_dur_hdr *icmp_hdr = (void *)pi->packet+IPV4_HEADER_OFFSET+IPV4_HEADER_LENGTH;
ICMPH_TYPE_SET(icmp_hdr, type);
ICMPH_CODE_SET(icmp_hdr, code);
ICMPH_UNUSED_SET(icmp_hdr);
memcpy(icmp_packet+ICMP_TIME_EX_IP_HEADER_OFFSET, old_packet, IPV4_HEADER_LENGTH + 8);
ICMPH_CHKSUM_SET(icmp_hdr, 0);
ICMPH_CHKSUM_SET(icmp_hdr, htons(calc_checksum(icmp_packet, pi->len-IPV4_HEADER_OFFSET-IPV4_HEADER_LENGTH)));
free(old_packet);
return 0;
}
