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https://github.com/lwip-tcpip/lwip.git
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Added code to free the oldest packets if the IP_REASS_MAX_PBUFS limit is reached or MEMP_REASSDATA is empty.
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goldsimon
parent
c41508cc8d
commit
1f08a5e5f5
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@ -47,6 +47,31 @@
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#include <string.h>
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#if IP_REASSEMBLY
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/**
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* The IP reassembly code currently has the following limitations:
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* - IP header options are not supported
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* - fragments must not overlap (e.g. due to different routes),
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* currently, overlapping or duplicate fragments are thrown away
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* if IP_REASS_CHECK_OVERLAP=1 (the default)!
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*
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* @todo: work with IP header options
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*/
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/** Setting this to 0, you can turn off checking the fragments for overlapping
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* regions. The code gets a little smaller. Only use this if you know that
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* overlapping won't occur on your network! */
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#ifndef IP_REASS_CHECK_OVERLAP
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#define IP_REASS_CHECK_OVERLAP 1
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#endif /* IP_REASS_CHECK_OVERLAP */
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/** Set to 0 to prevent freeing the oldest packet when the reassembly buffer is
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* full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
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* Packets will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
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* is set to 1, so one packet can be reassembled at a time, only. */
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#ifndef IP_REASS_FREE_OLDEST
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#define IP_REASS_FREE_OLDEST 1
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#endif /* IP_REASS_FREE_OLDEST */
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#define IP_REASS_FLAG_LASTFRAG 0x01
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/** This is a helper struct which holds the starting
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@ -61,35 +86,23 @@ struct ip_reass_helper {
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u16_t end;
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};
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#define IP_ADDRESSES_AND_ID_MATCH(iphdrA, iphdrB) \
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(ip_addr_cmp(&(iphdrA)->src, &(iphdrB)->src) && \
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ip_addr_cmp(&(iphdrA)->dest, &(iphdrB)->dest) && \
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IPH_ID(iphdrA) == IPH_ID(iphdrB)) ? 1 : 0
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/* global variables */
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static struct ip_reassdata *reasspackets;
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static u16_t ip_reass_pbufcount;
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#endif /* IP_REASSEMBLY */
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#if IP_REASSEMBLY
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/**
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* The IP reassembly code currently has the following limitations:
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* - IP header options are not supported
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* - fragments must not overlap (e.g. due to different routes),
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* currently, overlapping or duplicate fragments are thrown away
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* if IP_REASS_CHECK_OVERLAP=1 (the default)!
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*
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* @todo: work with IP header options
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* @todo: free the oldest entry when the MEMP_REASSDATA pool is empty or
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* the IP_REASS_MAX_PBUFS limit is reached
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*/
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#ifndef IP_REASS_CHECK_OVERLAP
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#define IP_REASS_CHECK_OVERLAP 1
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#endif /* IP_REASS_CHECK_OVERLAP */
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/* function prototypes */
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static void dequeue_packet(struct ip_reassdata *ipr, struct ip_reassdata *prev);
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static void ip_reass_dequeue_packet(struct ip_reassdata *ipr, struct ip_reassdata *prev);
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/**
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* Reassembly timer base function
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* for both NO_SYS == 0 and 1 (!).
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*
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* Should be called every 1000 msec.
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* Should be called every 1000 msec (defined by IP_TMR_INTERVAL).
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*/
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void
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ip_reass_tmr(void)
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@ -129,26 +142,106 @@ ip_reass_tmr(void)
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/* Then, unchain the struct ip_reassdata from the list and free it. */
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del = r;
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r = r->next;
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dequeue_packet(del, prev);
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ip_reass_dequeue_packet(del, prev);
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}
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}
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}
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#if IP_REASS_FREE_OLDEST
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/**
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* Free the oldest packet to make room for enqueueing new fragments.
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* The packet 'fraghdr' belongs to is not freed!
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*
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* @param fraghdr IP header of the current fragment
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* @param pbufs_needed number of pbufs needed to enqueue
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* (used for freeing other packets if not enough space)
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* @return the number of pbufs freed
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*/
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static int
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ip_reass_remove_oldest_packet(struct ip_hdr *fraghdr, int pbufs_needed)
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{
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/* @todo Can't we simply remove the last packet in the
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* linked list behind reasspackets?
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*/
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struct ip_reassdata *r, *oldest, *prev;
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int pbufs_freed = 0, pbufs_freed_current;
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int other_packets;
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/* Free packets until being allowed to enqueue 'pbufs_needed' pbufs,
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* but don't free the packet that 'fraghdr' belongs to! */
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do {
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oldest = NULL;
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prev = NULL;
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other_packets = 0;
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r = reasspackets;
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while (r != NULL) {
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if (!IP_ADDRESSES_AND_ID_MATCH(&r->iphdr, fraghdr)) {
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/* Not the same packet as fraghdr */
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other_packets++;
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if (oldest == NULL) {
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oldest = r;
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} else if (r->timer <= oldest->timer) {
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/* older than the previous oldest */
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oldest = r;
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}
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}
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if (r->next != NULL) {
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prev = r;
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}
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r = r->next;
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}
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if (oldest != NULL) {
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struct ip_reass_helper *iprh;
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struct pbuf *p = oldest->p;
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LWIP_ASSERT("prev != oldest", prev != oldest);
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if (prev != NULL) {
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LWIP_ASSERT("prev->next == oldest", prev->next == oldest);
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}
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/* Free all pbufs from all fragments enqueued for this packet. */
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pbufs_freed_current = 0;
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while (p != NULL) {
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pbufs_freed_current += pbuf_clen(p);
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iprh = (struct ip_reass_helper*)p->payload;
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p = iprh->next_pbuf;
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}
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/* Free the helper struct. */
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ip_reass_dequeue_packet(oldest, prev);
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LWIP_ASSERT("ip_reass_pbufcount >= pbufs_freed_current", ip_reass_pbufcount >= pbufs_freed_current);
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/* Update the pbuf counter. */
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ip_reass_pbufcount -= pbufs_freed_current;
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pbufs_freed += pbufs_freed_current;
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}
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} while ((pbufs_freed < pbufs_needed) && (other_packets > 1));
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return pbufs_freed;
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}
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#endif /* IP_REASS_FREE_OLDEST */
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/**
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* Enqueues a new fragment into the fragment queue
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* @param fraghdr points to the new fragments IP hdr
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* @param clen number of pbufs needed to enqueue (used for freeing other packets if not enough space)
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* @return A pointer to the queue location into which the fragment was enqueued
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*/
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static struct ip_reassdata*
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enqueue_new_packet(struct ip_hdr *fraghdr)
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ip_reass_enqueue_new_packet(struct ip_hdr *fraghdr, int clen)
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{
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struct ip_reassdata* ipr;
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/* No matching previous fragment found, allocate a new reassdata struct */
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ipr = memp_malloc(MEMP_REASSDATA);
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if (ipr == NULL) {
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IPFRAG_STATS_INC(ip_frag.memerr);
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LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct"));
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return NULL;
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#if IP_REASS_FREE_OLDEST
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if (ip_reass_remove_oldest_packet(fraghdr, clen) >= clen) {
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ipr = memp_malloc(MEMP_REASSDATA);
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}
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if (ipr == NULL)
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#endif /* IP_REASS_FREE_OLDEST */
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{
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IPFRAG_STATS_INC(ip_frag.memerr);
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LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct"));
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return NULL;
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}
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}
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memset(ipr, 0, sizeof(struct ip_reassdata));
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ipr->timer = IP_REASS_MAXAGE;
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@ -167,7 +260,7 @@ enqueue_new_packet(struct ip_hdr *fraghdr)
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* @param ipr points to the queue entry to dequeue
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*/
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static void
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dequeue_packet(struct ip_reassdata *ipr, struct ip_reassdata *prev)
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ip_reass_dequeue_packet(struct ip_reassdata *ipr, struct ip_reassdata *prev)
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{
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/* dequeue the reass struct */
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@ -194,7 +287,7 @@ dequeue_packet(struct ip_reassdata *ipr, struct ip_reassdata *prev)
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* @return 0 if invalid, >0 otherwise
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*/
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static int
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chain_frag_into_packet_and_validate(struct ip_reassdata *ipr, struct pbuf *new_p)
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ip_reass_chain_frag_into_packet_and_validate(struct ip_reassdata *ipr, struct pbuf *new_p)
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{
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struct ip_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
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struct pbuf *q;
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@ -363,11 +456,18 @@ ip_reass(struct pbuf *p)
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/* Check if we are allowed to enqueue more packets. */
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clen = pbuf_clen(p);
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if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
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LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d",
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ip_reass_pbufcount,clen,IP_REASS_MAX_PBUFS));
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IPFRAG_STATS_INC(ip_frag.memerr);
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/* drop this pbuf */
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goto nullreturn;
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#if IP_REASS_FREE_OLDEST
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if (!ip_reass_remove_oldest_packet(fraghdr, clen) ||
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((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
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#endif /* IP_REASS_FREE_OLDEST */
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{
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/* No packet could be freed and still too many pbufs enqueued */
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LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d",
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ip_reass_pbufcount,clen,IP_REASS_MAX_PBUFS));
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IPFRAG_STATS_INC(ip_frag.memerr);
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/* drop this pbuf */
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goto nullreturn;
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}
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}
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/* Look for the packet the fragment belongs to in the current packet queue,
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@ -376,9 +476,7 @@ ip_reass(struct pbuf *p)
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/* Check if the incoming fragment matches the one currently present
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in the reassembly buffer. If so, we proceed with copying the
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fragment into the buffer. */
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if (ip_addr_cmp(&ipr->iphdr.src, &fraghdr->src) &&
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ip_addr_cmp(&ipr->iphdr.dest, &fraghdr->dest) &&
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IPH_ID(&ipr->iphdr) == IPH_ID(fraghdr)) {
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if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
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LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
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ntohs(IPH_ID(fraghdr))));
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IPFRAG_STATS_INC(ip_frag.cachehit);
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@ -389,7 +487,7 @@ ip_reass(struct pbuf *p)
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if (ipr == NULL) {
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/* Enqueue a new packet into the packet queue */
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ipr = enqueue_new_packet(fraghdr);
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ipr = ip_reass_enqueue_new_packet(fraghdr, clen);
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/* Bail if unable to enqueue */
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if(ipr == NULL) {
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goto nullreturn;
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@ -412,7 +510,7 @@ ip_reass(struct pbuf *p)
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}
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/* find the right place to insert this pbuf */
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/* @todo: trim pbufs if fragments are overlapping */
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if (chain_frag_into_packet_and_validate(ipr, p)) {
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if (ip_reass_chain_frag_into_packet_and_validate(ipr, p)) {
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/* the totally last fragment (flag more fragments = 0) was received at least
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* once AND all fragments are received */
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ipr->packet_len += IP_HLEN;
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@ -441,7 +539,7 @@ ip_reass(struct pbuf *p)
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r = iprh->next_pbuf;
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}
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/* release the sources allocate for the fragment queue entry */
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dequeue_packet(ipr, ipr_prev);
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ip_reass_dequeue_packet(ipr, ipr_prev);
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/* and adjust the number of pbufs currently queued for reassembly. */
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ip_reass_pbufcount -= pbuf_clen(p);
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