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Changed IP_REASSEMBLY to enqueue the received pbufs so that multiple packets can be reassembled simultaneously and no static reassembly buffer is needed.

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This commit is contained in:
goldsimon 2007-10-06 15:24:43 +00:00
parent cb71d6d393
commit b7ef6077df
7 changed files with 381 additions and 183 deletions
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5
CHANGELOG
View File

@ -19,6 +19,11 @@ HISTORY
++ New features:
2007-10-06 Simon Goldschmidt
* ip_frag.c, memp.c, mib2.c, ip_frag.h, memp_std.h, opt.h: Changed IP_REASSEMBLY
to enqueue the received pbufs so that multiple packets can be reassembled
simultaneously and no static reassembly buffer is needed.
2007-10-05 Simon Goldschmidt
* tcpip.c, etharp.h, etharp.c: moved ethernet_input from tcpip.c to etharp.c so
all netifs (or ports) can use it.

515
src/core/ipv4/ip_frag.c
View File

@ -47,29 +47,48 @@
#include <string.h>
#if IP_REASSEMBLY
static u8_t ip_reassbuf[IP_HLEN + IP_REASS_BUFSIZE];
static u8_t ip_reassbitmap[IP_REASS_BUFSIZE / (8 * 8) + 1];
static const u8_t bitmap_bits[8] = { 0xff, 0x7f, 0x3f, 0x1f,
0x0f, 0x07, 0x03, 0x01
};
static u16_t ip_reasslen;
static u8_t ip_reassflags;
#define IP_REASS_FLAG_LASTFRAG 0x01
static u8_t ip_reasstmr;
/** This is a helper struct which holds the starting
* offset and the ending offset of this fragment to
* easily chain the fragments.
* It must be packet because the memory of the ip header
* of fragments is misused for holding this data.
*/
struct ip_reass_helper {
struct pbuf *next_pbuf;
u16_t start;
u16_t end;
};
static struct ip_reassdata *reasspackets;
static u16_t ip_reass_pbufcount;
#endif /* IP_REASSEMBLY */
#if IP_REASSEMBLY
/**
* The IP reassembly code currently has the following limitations:
* - IP header options are not supported
* - fragments must not overlap (e.g. due to different routes),
* currently, overlapping fragments will produce undefined results!
*
* @todo: throw away overlapping fragments!
* @todo: work with IP header options
* @todo: check what happens if the same fragment arrives twice or overlapping fragments arrive!
*/
/* function prototypes */
static void dequeue_packet(struct ip_reassdata *ipr, struct ip_reassdata *prev);
/**
* Initializes IP reassembly states.
*/
void
ip_reass_init(void)
{
ip_reasstmr = 0;
ip_reassflags = 0;
ip_reasslen = 0;
memset(ip_reassbitmap, 0, sizeof(ip_reassbitmap));
LWIP_ASSERT("sizeof(struct ip_reass_helper) <= IP_HLEN",
sizeof(struct ip_reass_helper) <= IP_HLEN);
LWIP_ASSERT("ip_reass_pbufcount!=0",ip_reass_pbufcount==0);
}
/**
@ -81,14 +100,212 @@ ip_reass_init(void)
void
ip_reass_tmr(void)
{
if (ip_reasstmr > 0) {
ip_reasstmr--;
LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n",(u16_t)ip_reasstmr));
if (ip_reasstmr == 0) {
/* reassembly timed out */
struct ip_reassdata *r, *prev = NULL;
struct ip_reass_helper *iprh;
r = reasspackets;
while (r != NULL) {
/* Decrement the timer. Once it reaches 0,
* clean up the incomplete fragment assembly */
if (r->timer > 0) {
r->timer--;
LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n",(u16_t)r->timer));
prev = r;
r = r->next;
} else {
/* reassembly timed out */
struct pbuf *p;
struct ip_reassdata *del;
LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer timed out"));
snmp_inc_ipreasmfails();
/* First, free all received pbufs. The individual pbufs need to be released
separately as they have not yet been chained */
p = r->p;
while (p != NULL) {
struct pbuf *pcur;
iprh = (struct ip_reass_helper *)p->payload;
pcur = p;
p = iprh->next_pbuf;
pbuf_free(pcur);
ip_reass_pbufcount--;
}
/* Then, unchain the struct ip_reassdata from the list and free it. */
del = r;
r = r->next;
dequeue_packet(del, prev);
}
}
}
/**
* Enqueues a new fragment into the fragment queue
* @param fraghdr points to the new fragments IP hdr
* @return A pointer to the queue location into which the fragment was enqueued
*/
static struct ip_reassdata*
enqueue_new_packet(struct ip_hdr *fraghdr) {
struct ip_reassdata* ipr;
/* No matching previous fragment found, allocate a new reassdata struct */
ipr = memp_malloc(MEMP_REASSDATA);
if (ipr == NULL) {
IPFRAG_STATS_INC(ip_frag.memerr);
LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct"));
return NULL;
}
memset(ipr, 0, sizeof(struct ip_reassdata));
ipr->timer = IP_REASS_MAXAGE;
/* enqueue the new structure to the front of the list */
ipr->next = reasspackets;
reasspackets = ipr;
/* copy the ip header for later tests and input */
/* @todo: no ip options supported? */
SMEMCPY(&(ipr->iphdr), fraghdr, IP_HLEN);
return ipr;
}
/**
* Dequeues a packet from the packet queue. Doesn't deallocate the pbufs.
* @param ipr points to the queue entry to dequeue
*/
static void
dequeue_packet(struct ip_reassdata *ipr, struct ip_reassdata *prev) {
/* dequeue the reass struct */
if (reasspackets == ipr) {
/* it was the first in the list */
reasspackets = ipr->next;
} else {
/* it wasn't the first, so it must have a valid 'prev' */
LWIP_ASSERT("sanity check linked list", prev != NULL);
prev->next = ipr->next;
}
/* now we can free the ip_reass struct */
memp_free(MEMP_REASSDATA, ipr);
}
/**
* Chain a new pbuf into the pbuf list that composes the datagram. The pbuf list
* will grow over time as new pbufs are rx.
* Also checks that the datagram passes basic continuity checks (if the last
* fragment was received at least once).
* @param root_p points to the 'root' pbuf for the current datagram being assembled.
* @param new_p points to the pbuf for the current fragment
* @return 0 if invalid, >0 otherwise
*/
static int
chain_frag_into_packet(struct ip_reassdata *ipr, struct pbuf *new_p) {
struct ip_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
struct pbuf *q;
u16_t offset,len;
struct ip_hdr *fraghdr;
int valid = 1;
/* Extract length and fragment offset from current fragment */
fraghdr = (struct ip_hdr*)new_p->payload;
len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
/* overwrite the fragment's ip header from the pbuf with our helper struct,
* and setup the embedded helper structure. */
iprh = (struct ip_reass_helper*)new_p->payload;
iprh->next_pbuf = NULL;
iprh->start = offset;
iprh->end = offset + len;
/* Iterate through until we either get to the end of the list (append),
* or we find on with a larger offset (insert). */
for (q = ipr->p; q != NULL;) {
iprh_tmp = (struct ip_reass_helper*)q->payload;
if (iprh->start < iprh_tmp->start) {
/* the new pbuf should be inserted before this */
iprh->next_pbuf = q;
if (iprh_prev != NULL) {
/* not the fragment with the lowest offset */
iprh_prev->next_pbuf = new_p;
} else {
/* fragment with the lowest offset */
ipr->p = new_p;
}
break;
} else {
/* Check if the fragments received so far have not wholes. */
if (iprh_prev == NULL) {
if (iprh_tmp->start != 0) {
/* the first fragment doesn't start at 0 */
valid = 0;
}
} else {
if (iprh_prev->end != iprh_tmp->start) {
/* There is a fragment missing between the current
* and the previous fragment */
valid = 0;
}
}
}
q = iprh_tmp->next_pbuf;
iprh_prev = iprh_tmp;
}
/* If q is NULL, then we made it to the end of the list. Determine what to do now */
if (q == NULL) {
if (iprh_prev != NULL) {
/* this is (for now), the fragment with the highest offset:
* chain it to the last fragment */
iprh_prev->next_pbuf = new_p;
if (iprh_prev->end != iprh->start) {
valid = 0;
}
} else {
/* this is the first fragment we ever received for this ip packet */
ipr->p = new_p;
}
}
/* If we already received the last fragment */
if ((ipr->flags & IP_REASS_FLAG_LASTFRAG) != 0) {
/* and had no wholes so far */
if (valid) {
/* then check if the rest of the fragments is here */
/* Check if the queue starts with the first packet */
if (((struct ip_reass_helper*)ipr->p->payload)->start != 0) {
valid = 0;
} else {
/* and check that there are no wholes after this packet */
iprh_prev = iprh;
q = iprh->next_pbuf;
while (q != NULL) {
iprh = (struct ip_reass_helper*)q->payload;
if (iprh_prev->end != iprh->start) {
valid = 0;
break;
}
iprh_prev = iprh_tmp;
q = iprh->next_pbuf;
}
/* if still valid, all fragments are received
* (because to the MF==0 already arrived */
if (valid) {
LWIP_ASSERT("sanity check", ipr->p != NULL);
LWIP_ASSERT("sanity check",
((struct ip_reass_helper*)ipr->p->payload) != iprh);
LWIP_ASSERT("validate_datagram:next_pbuf!=NULL",
iprh->next_pbuf == NULL);
LWIP_ASSERT("validate_datagram:datagram end!=packet len",
iprh->end == ipr->packet_len);
}
}
}
/* If valid is 0 here, there are some fragments missing in the middle
* (since MF == 0 has already arrived). Such packets simply time out if
* no more fragments are received... */
return valid;
}
/* If we come here, not all fragments were received, yet! */
return 0; /* not yet valid! */
}
/**
@ -100,175 +317,123 @@ ip_reass_tmr(void)
struct pbuf *
ip_reass(struct pbuf *p)
{
struct pbuf *q;
struct ip_hdr *fraghdr, *iphdr;
struct pbuf *r;
struct ip_hdr *fraghdr;
struct ip_reassdata *ipr;
struct ip_reass_helper *iprh;
u16_t offset, len;
u16_t i;
u8_t clen;
struct ip_reassdata *ipr_prev = NULL;
IPFRAG_STATS_INC(ip_frag.recv);
snmp_inc_ipreasmreqds();
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"));
SMEMCPY(iphdr, fraghdr, IP_HLEN);
ip_reasstmr = IP_REASS_MAXAGE;
ip_reassflags = 0;
/* Clear the bitmap. */
memset(ip_reassbitmap, 0, sizeof(ip_reassbitmap));
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!"));
IPFRAG_STATS_INC(ip_frag.err);
goto nullreturn;
}
/* 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;
offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
/* 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;
snmp_inc_ipreasmfails();
/* Check if we are allowed to enqueue more packets. */
clen = pbuf_clen(p);
if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d",
ip_reass_pbufcount,clen,IP_REASS_MAX_PBUFS));
IPFRAG_STATS_INC(ip_frag.memerr);
/* drop this pbuf */
goto nullreturn;
}
/* Look for the packet the fragment belongs to in the current packet queue,
* remembering the previous in the queue for later dequeueing. */
for (ipr = reasspackets; 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_addr_cmp(&ipr->iphdr.src, &fraghdr->src) &&
ip_addr_cmp(&ipr->iphdr.dest, &fraghdr->dest) &&
IPH_ID(&ipr->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);
break;
}
ipr_prev = ipr;
}
if (ipr == NULL) {
/* Enqueue a new packet into the packet queue */
ipr = enqueue_new_packet(fraghdr);
/* Bail if unable to enqueue */
if(ipr == NULL) {
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;
pbuf_copy_partial(p, &ip_reassbuf[IP_HLEN + offset], len, i);
/* 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);
snmp_inc_ipreasmoks();
} else {
LWIP_DEBUGF(IP_REASS_DEBUG,
("ip_reass: pbuf_alloc(PBUF_LINK, ip_reasslen=%"U16_F", PBUF_POOL) failed\n", ip_reasslen));
IPFRAG_STATS_INC(ip_frag.memerr);
snmp_inc_ipreasmfails();
}
LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: p %p\n", (void*)p));
return p;
}
}
/* 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 ((ntohs(IPH_OFFSET(fraghdr)) & IP_MF) == 0) {
ipr->flags |= IP_REASS_FLAG_LASTFRAG;
ipr->packet_len = offset + len;
LWIP_DEBUGF(IP_REASS_DEBUG,
("ip_reass: last fragment seen, total len %"S16_F"\n",
ipr->packet_len));
}
/* find the right place to insert this pbuf */
/* @todo: trim pbufs if fragments are overlapping */
if (chain_frag_into_packet(ipr, p)) {
/* the totally last fragment (flag more fragments = 0) was received at least
* once AND all fragments are received */
ipr->packet_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->packet_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 */
dequeue_packet(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 packet is not (yet?) reassembled completely */
LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out", ip_reass_pbufcount));
return NULL;
nullreturn:
LWIP_DEBUGF(IP_REASS_DEBUG,("nullreturn"));
IPFRAG_STATS_INC(ip_frag.drop);
pbuf_free(p);
return NULL;
@ -429,8 +594,8 @@ ip_frag(struct pbuf *p, struct netif *netif, struct ip_addr *dest)
pbuf_free(header);
} else {
LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n"));
pbuf_free(rambuf);
return ERR_MEM;
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

1
src/core/memp.c
View File

@ -50,6 +50,7 @@
#include "lwip/sys.h"
#include "lwip/stats.h"
#include "netif/etharp.h"
#include "lwip/ip_frag.h"
#include <string.h>

7
src/core/snmp/mib2.c
View File

@ -3027,7 +3027,12 @@ ip_addrentry_get_value(struct obj_def *od, u16_t len, void *value)
{
s32_t *sint_ptr = value;
#if IP_REASSEMBLY
*sint_ptr = (IP_HLEN + IP_REASS_BUFSIZE);
/* @todo The theoretical maximum is IP_REASS_MAX_PBUFS * size of the pbufs,
* but only if receiving one fragmented packet at a time.
* The current solution is to calculate for 2 simultaneous packets...
*/
*sint_ptr = (IP_HLEN + ((IP_REASS_MAX_PBUFS/2) *
(PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN - IP_HLEN)));
#else
/** @todo returning MTU would be a bad thing and
returning a wild guess like '576' isn't good either */

13
src/include/ipv4/lwip/ip_frag.h
View File

@ -38,6 +38,7 @@
#include "lwip/pbuf.h"
#include "lwip/netif.h"
#include "lwip/ip_addr.h"
#include "lwip/ip.h"
#ifdef __cplusplus
extern "C" {
@ -47,6 +48,18 @@ extern "C" {
/* The IP reassembly timer interval in milliseconds. */
#define IP_TMR_INTERVAL 1000
/* IP reassembly helper struct.
* This is exported because memp needs to know the size.
*/
struct ip_reassdata {
struct ip_reassdata *next;
struct pbuf *p;
struct ip_hdr iphdr;
u16_t packet_len;
u8_t flags;
u8_t timer;
};
void ip_reass_init(void);
void ip_reass_tmr(void);
struct pbuf * ip_reass(struct pbuf *p);

4
src/include/lwip/memp_std.h
View File

@ -43,6 +43,10 @@ LWIP_MEMPOOL(TCP_PCB_LISTEN, MEMP_NUM_TCP_PCB_LISTEN, sizeof(struct tcp_pcb_lis
LWIP_MEMPOOL(TCP_SEG, MEMP_NUM_TCP_SEG, sizeof(struct tcp_seg), "TCP_SEG")
#endif /* LWIP_TCP */
#if IP_REASSEMBLY
LWIP_MEMPOOL(REASSDATA, MEMP_NUM_REASSDATA, sizeof(struct ip_reassdata), "REASSDATA")
#endif
#if LWIP_NETCONN
LWIP_MEMPOOL(NETBUF, MEMP_NUM_NETBUF, sizeof(struct netbuf), "NETBUF")
LWIP_MEMPOOL(NETCONN, MEMP_NUM_NETCONN, sizeof(struct netconn), "NETCONN")

19
src/include/lwip/opt.h
View File

@ -162,9 +162,9 @@
------------------------------------------------
*/
/**
* MEMP_NUM_PBUF: the number of memp struct pbufs. If the application
* sends a lot of data out of ROM (or other static memory), this
* should be set high.
* MEMP_NUM_PBUF: the number of memp struct pbufs (used for PBUF_ROM and PBUF_REF).
* If the application sends a lot of data out of ROM (or other static memory),
* this should be set high.
*/
#ifndef MEMP_NUM_PBUF
#define MEMP_NUM_PBUF 16
@ -361,17 +361,22 @@
#endif
/**
* IP_REASS_MAXAGE: IP reassemly default age in seconds.
* IP_REASS_MAXAGE: Maximum time (in multiples of IP_TMR_INTERVAL - so seconds, normally)
* a fragmented IP packet waits for all fragments to arrive. If not all fragments arrived
* in this time, the whole packet is discarded.
*/
#ifndef IP_REASS_MAXAGE
#define IP_REASS_MAXAGE 3
#endif
/**
* IP_REASS_BUFSIZE: IP reassembly buffer size (minus IP header).
* IP_REASS_MAX_PBUFS: Total maximum amount of pbufs waiting to be reassembled.
* Since the received pbufs are enqueued, be sure to configure
* PBUF_POOL_SIZE > IP_REASS_MAX_PBUFS so that the stack is still able to receive
* packets even if the maximum amount of fragments is enqueued for reassembly!
*/
#ifndef IP_REASS_BUFSIZE
#define IP_REASS_BUFSIZE 5760
#ifndef IP_REASS_MAX_PBUFS
#define IP_REASS_MAX_PBUFS 10
#endif
/**