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Shrinked ICMP code, added option to NOT check icoming ECHO pbuf for size (just use it): LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN

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This commit is contained in:
goldsimon 2009-05-09 08:36:36 +00:00
parent c752e5731c
commit 105d72a3c2
3 changed files with 58 additions and 66 deletions
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4
CHANGELOG
View File

@ -19,6 +19,10 @@ HISTORY
++ New features:
2009-05-09 Simon Goldschmidt
* icmp.h, icmp.c: Shrinked ICMP code, added option to NOT check icoming
ECHO pbuf for size (just use it): LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
2009-05-05 Simon Goldschmidt, Jakob Stoklund Olesen
* ip.h, ip.c: Added ip_current_netif() & ip_current_header() to receive
extended info about the currently received packet.

87
src/core/ipv4/icmp.c
View File

@ -53,9 +53,18 @@
#include <string.h>
/** Small optimization: set to 0 if incoming PBUF_POOL pbuf always can be
* used to modify and send a response packet (and to 1 if this is not the case,
* e.g. when link header is stripped of when receiving) */
#ifndef LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
#define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1
#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
/* The amount of data from the original packet to return in a dest-unreachable */
#define ICMP_DEST_UNREACH_DATASIZE 8
static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code);
/**
* Processes ICMP input packets, called from ip_input().
*
@ -130,6 +139,7 @@ icmp_input(struct pbuf *p, struct netif *inp)
snmp_inc_icmpinerrors();
return;
}
#if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
/* p is not big enough to contain link headers
* allocate a new one and copy p into it
@ -170,6 +180,7 @@ icmp_input(struct pbuf *p, struct netif *inp)
goto memerr;
}
}
#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. */
@ -222,11 +233,13 @@ lenerr:
ICMP_STATS_INC(icmp.lenerr);
snmp_inc_icmpinerrors();
return;
#if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
memerr:
pbuf_free(p);
ICMP_STATS_INC(icmp.err);
snmp_inc_icmpinerrors();
return;
#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
}
/**
@ -241,40 +254,7 @@ memerr:
void
icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
{
struct pbuf *q;
struct ip_hdr *iphdr;
struct icmp_dur_hdr *idur;
/* ICMP header + IP header + 8 bytes of data */
q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
PBUF_RAM);
if (q == NULL) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n"));
return;
}
LWIP_ASSERT("check that first pbuf can hold icmp message",
(q->len >= (sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
iphdr = p->payload;
idur = q->payload;
ICMPH_TYPE_SET(idur, ICMP_DUR);
ICMPH_CODE_SET(idur, t);
SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_dur_hdr), p->payload,
IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
/* calculate checksum */
idur->chksum = 0;
idur->chksum = inet_chksum(idur, q->len);
ICMP_STATS_INC(icmp.xmit);
/* increase number of messages attempted to send */
snmp_inc_icmpoutmsgs();
/* increase number of destination unreachable messages attempted to send */
snmp_inc_icmpoutdestunreachs();
ip_output(q, NULL, &(iphdr->src), ICMP_TTL, 0, IP_PROTO_ICMP);
pbuf_free(q);
icmp_send_response(p, ICMP_DUR, t);
}
#if IP_FORWARD || IP_REASSEMBLY
@ -287,20 +267,37 @@ icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
*/
void
icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
{
icmp_send_response(p, ICMP_TE, t);
}
#endif /* IP_FORWARD || IP_REASSEMBLY */
/**
* Send an icmp packet in response to an incoming packet.
*
* @param p the input packet for which the 'unreachable' should be sent,
* p->payload pointing to the IP header
* @param type Type of the ICMP header
* @param code Code of the ICMP header
*/
static void
icmp_send_response(struct pbuf *p, u8_t type, u8_t code)
{
struct pbuf *q;
struct ip_hdr *iphdr;
struct icmp_te_hdr *tehdr;
/* we can use the echo header here */
struct icmp_echo_hdr *icmphdr;
/* ICMP header + IP header + 8 bytes of data */
q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
PBUF_RAM);
if (q == NULL) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n"));
return;
}
LWIP_ASSERT("check that first pbuf can hold icmp message",
(q->len >= (sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
(q->len >= (sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
iphdr = p->payload;
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));
@ -309,17 +306,19 @@ icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest));
LWIP_DEBUGF(ICMP_DEBUG, ("\n"));
tehdr = q->payload;
ICMPH_TYPE_SET(tehdr, ICMP_TE);
ICMPH_CODE_SET(tehdr, t);
icmphdr = q->payload;
icmphdr->type = type;
icmphdr->code = code;
icmphdr->id = 0;
icmphdr->seqno = 0;
/* copy fields from original packet */
SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_dur_hdr), (u8_t *)p->payload,
SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_echo_hdr), (u8_t *)p->payload,
IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
/* calculate checksum */
tehdr->chksum = 0;
tehdr->chksum = inet_chksum(tehdr, q->len);
icmphdr->chksum = 0;
icmphdr->chksum = inet_chksum(icmphdr, q->len);
ICMP_STATS_INC(icmp.xmit);
/* increase number of messages attempted to send */
snmp_inc_icmpoutmsgs();
@ -329,6 +328,4 @@ icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
pbuf_free(q);
}
#endif /* IP_FORWARD */
#endif /* LWIP_ICMP */

33
src/include/ipv4/lwip/icmp.h
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@ -78,39 +78,30 @@ void icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t);
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/bpstruct.h"
#endif
/** This is the standard ICMP header only that the u32_t data
* is splitted to two u16_t like ICMP echo needs it.
* This header is also used for other ICMP types that do not
* use the data part.
*/
PACK_STRUCT_BEGIN
struct icmp_echo_hdr {
PACK_STRUCT_FIELD(u16_t _type_code);
PACK_STRUCT_FIELD(u8_t type);
PACK_STRUCT_FIELD(u8_t code);
PACK_STRUCT_FIELD(u16_t chksum);
PACK_STRUCT_FIELD(u16_t id);
PACK_STRUCT_FIELD(u16_t seqno);
} PACK_STRUCT_STRUCT;
PACK_STRUCT_END
PACK_STRUCT_BEGIN
struct icmp_dur_hdr {
PACK_STRUCT_FIELD(u16_t _type_code);
PACK_STRUCT_FIELD(u16_t chksum);
PACK_STRUCT_FIELD(u32_t unused);
} PACK_STRUCT_STRUCT;
PACK_STRUCT_END
PACK_STRUCT_BEGIN
struct icmp_te_hdr {
PACK_STRUCT_FIELD(u16_t _type_code);
PACK_STRUCT_FIELD(u16_t chksum);
PACK_STRUCT_FIELD(u32_t unused);
} PACK_STRUCT_STRUCT;
PACK_STRUCT_END
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/epstruct.h"
#endif
#define ICMPH_TYPE(hdr) (ntohs((hdr)->_type_code) >> 8)
#define ICMPH_CODE(hdr) (ntohs((hdr)->_type_code) & 0xff)
#define ICMPH_TYPE(hdr) ((hdr)->type)
#define ICMPH_CODE(hdr) ((hdr)->code)
#define ICMPH_TYPE_SET(hdr, type) ((hdr)->_type_code = htons(ICMPH_CODE(hdr) | ((type) << 8)))
#define ICMPH_CODE_SET(hdr, code) ((hdr)->_type_code = htons((code) | (ICMPH_TYPE(hdr) << 8)))
/** Combines type and code to an u16_t */
#define ICMPH_TYPE_SET(hdr, t) ((hdr)->type = (t))
#define ICMPH_CODE_SET(hdr, c) ((hdr)->code = (c))
#ifdef __cplusplus
}