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-rw-r--r--ChangeLog3
-rw-r--r--iftop.c91
2 files changed, 56 insertions, 38 deletions
diff --git a/ChangeLog b/ChangeLog
index a69e22a..9efcb95 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,9 @@ Unattributed items are by Paul Warren and Chris Lightfoot.
1.0
+* Fix handling of short packets
+ Frédéric Perrin <fperrin@brocade.com>
+
* Fix MAC address display
Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
diff --git a/iftop.c b/iftop.c
index 3d5d622..aaec6aa 100644
--- a/iftop.c
+++ b/iftop.c
@@ -249,16 +249,16 @@ void assign_addr_pair(addr_pair* ap, struct ip* iptr, int flip) {
}
}
-static void handle_ip_packet(struct ip* iptr, int hw_dir)
+static void handle_ip_packet(struct ip* iptr, int hw_dir, int pld_len)
{
int direction = 0; /* incoming */
+ int len;
history_type* ht;
union {
history_type **ht_pp;
void **void_pp;
} u_ht = { &ht };
addr_pair ap;
- unsigned int len = 0;
struct in6_addr scribdst; /* Scratch pad. */
struct in6_addr scribsrc; /* Scratch pad. */
/* Reinterpret packet type. */
@@ -268,7 +268,21 @@ static void handle_ip_packet(struct ip* iptr, int hw_dir)
tick(0);
- if( (IP_V(iptr) ==4 && options.netfilter == 0)
+ /*
+ * Sanity check: drop obviously short packets.
+ * pld_len comes from pcaphdr->len - sizeof(struct l2_header).
+ *
+ * It is assumed that the snaplen (currently hard-coded to 1000) is
+ * big enough to always capture the IP header past the L2 encap, and
+ * that pcap never truncates the packet to less than snaplen; in
+ * other words, that pcaphdr->caplen = MIN(pcaphdr->len, snaplen).
+ */
+ if (pld_len < sizeof (struct ip))
+ return;
+ if (IP_V(iptr) == 6 && pld_len < sizeof (struct ip6_hdr))
+ return;
+
+ if( (IP_V(iptr) == 4 && options.netfilter == 0)
|| (IP_V(iptr) == 6 && options.netfilter6 == 0) ) {
/*
* Net filter is off, so assign direction based on MAC address
@@ -424,7 +438,6 @@ static void handle_ip_packet(struct ip* iptr, int hw_dir)
break;
}
-
if(hash_find(history, &ap, u_ht.void_pp) == HASH_STATUS_KEY_NOT_FOUND) {
ht = history_create();
hash_insert(history, &ap, ht);
@@ -434,19 +447,13 @@ static void handle_ip_packet(struct ip* iptr, int hw_dir)
switch (options.bandwidth_unit) {
case OPTION_BW_BITS:
case OPTION_BW_BYTES:
- switch (IP_V(iptr)) {
- case 4:
- len = ntohs(iptr->ip_len);
- break;
- case 6:
- len = ntohs(ip6tr->ip6_plen) + 40;
- default:
- break;
- }
+ len = pld_len;
break;
case OPTION_BW_PKTS:
len = 1;
break;
+ default:
+ return;
}
/* Update record */
@@ -476,7 +483,7 @@ static void handle_ip_packet(struct ip* iptr, int hw_dir)
static void handle_raw_packet(unsigned char* args, const struct pcap_pkthdr* pkthdr, const unsigned char* packet)
{
- handle_ip_packet((struct ip*)packet, -1);
+ handle_ip_packet((struct ip*)packet, -1, pkthdr->len);
}
#ifdef DLT_PFLOG
@@ -490,18 +497,19 @@ static void handle_pflog_packet(unsigned char* args, const struct pcap_pkthdr* p
hdrlen = BPF_WORDALIGN(hdr->length);
length -= hdrlen;
packet += hdrlen;
- handle_ip_packet((struct ip*)packet, -1);
+ handle_ip_packet((struct ip*)packet, -1, length);
}
#endif
static void handle_null_packet(unsigned char* args, const struct pcap_pkthdr* pkthdr, const unsigned char* packet)
{
- handle_ip_packet((struct ip*)(packet + 4), -1);
+ handle_ip_packet((struct ip*)(packet + 4), -1, pkthdr->len);
}
-static void handle_llc_packet(const struct llc* llc, int dir) {
-
- struct ip* ip = (struct ip*)((void*)llc + sizeof(struct llc));
+static void handle_llc_packet(const struct llc* llc, int dir, int llclen) {
+ int hdrlen = sizeof(struct llc);
+ int pldlen = llclen - hdrlen;
+ struct ip* ip = (struct ip*)((void*)llc + hdrlen);
/* Taken from tcpdump/print-llc.c */
if(llc->ssap == LLCSAP_SNAP && llc->dsap == LLCSAP_SNAP
@@ -513,11 +521,11 @@ static void handle_llc_packet(const struct llc* llc, int dir) {
switch(orgcode) {
case OUI_ENCAP_ETHER:
case OUI_CISCO_90:
- handle_ip_packet(ip, dir);
+ handle_ip_packet(ip, dir, pldlen);
break;
case OUI_APPLETALK:
if(et == ETHERTYPE_ATALK) {
- handle_ip_packet(ip, dir);
+ handle_ip_packet(ip, dir, pldlen);
}
break;
default:;
@@ -529,33 +537,36 @@ static void handle_llc_packet(const struct llc* llc, int dir) {
static void handle_tokenring_packet(unsigned char* args, const struct pcap_pkthdr* pkthdr, const unsigned char* packet)
{
struct token_header *trp;
+ int hdrlen = 0;
int dir = -1;
trp = (struct token_header *)packet;
if(IS_SOURCE_ROUTED(trp)) {
- packet += RIF_LENGTH(trp);
+ hdrlen += RIF_LENGTH(trp);
}
- packet += TOKEN_HDRLEN;
+ hdrlen += TOKEN_HDRLEN;
+ packet += hdrlen;
if(memcmp(trp->token_shost, if_hw_addr, 6) == 0 ) {
/* packet leaving this i/f */
dir = 1;
- }
- else if(memcmp(trp->token_dhost, if_hw_addr, 6) == 0 || memcmp("\xFF\xFF\xFF\xFF\xFF\xFF", trp->token_dhost, 6) == 0) {
+ }
+ else if(memcmp(trp->token_dhost, if_hw_addr, 6) == 0 || memcmp("\xFF\xFF\xFF\xFF\xFF\xFF", trp->token_dhost, 6) == 0) {
/* packet entering this i/f */
dir = 0;
}
/* Only know how to deal with LLC encapsulated packets */
if(FRAME_TYPE(trp) == TOKEN_FC_LLC) {
- handle_llc_packet((struct llc*)packet, dir);
+ handle_llc_packet((struct llc*)packet, dir, pkthdr->len - hdrlen);
}
}
static void handle_ppp_packet(unsigned char* args, const struct pcap_pkthdr* pkthdr, const unsigned char* packet)
{
- register u_int caplen = pkthdr->caplen;
- u_int proto;
+ register u_int length = pkthdr->len;
+ register u_int caplen = pkthdr->caplen;
+ u_int proto;
if (caplen < 2)
return;
@@ -565,12 +576,14 @@ static void handle_ppp_packet(unsigned char* args, const struct pcap_pkthdr* pkt
return;
packet += 2;
+ length -= 2;
proto = EXTRACT_16BITS(packet);
packet += 2;
+ length -= 2;
if(proto == PPP_IP || proto == ETHERTYPE_IP || proto == ETHERTYPE_IPV6) {
- handle_ip_packet((struct ip*)packet, -1);
+ handle_ip_packet((struct ip*)packet, -1, length);
}
}
}
@@ -593,24 +606,25 @@ static void handle_cooked_packet(unsigned char *args, const struct pcap_pkthdr *
dir=1;
break;
}
- handle_ip_packet((struct ip*)(packet+SLL_HDR_LEN), dir);
+ handle_ip_packet((struct ip*)(packet+SLL_HDR_LEN), dir,
+ thdr->len - SLL_HDR_LEN);
}
#endif /* DLT_LINUX_SLL */
static void handle_eth_packet(unsigned char* args, const struct pcap_pkthdr* pkthdr, const unsigned char* packet)
{
struct ether_header *eptr;
- int ether_type;
- const unsigned char *payload;
+ int ether_type, hdrlen;
+
eptr = (struct ether_header*)packet;
ether_type = ntohs(eptr->ether_type);
- payload = packet + sizeof(struct ether_header);
+ hdrlen = sizeof(struct ether_header);
if(ether_type == ETHERTYPE_8021Q) {
struct vlan_8021q_header* vptr;
- vptr = (struct vlan_8021q_header*)payload;
+ vptr = (struct vlan_8021q_header*) (packet + hdrlen);
ether_type = ntohs(vptr->ether_type);
- payload += sizeof(struct vlan_8021q_header);
+ hdrlen += sizeof(struct vlan_8021q_header);
}
if(ether_type == ETHERTYPE_IP || ether_type == ETHERTYPE_IPV6) {
@@ -634,8 +648,8 @@ static void handle_eth_packet(unsigned char* args, const struct pcap_pkthdr* pkt
}
/* Distinguishing ip_hdr and ip6_hdr will be done later. */
- iptr = (struct ip*)(payload); /* alignment? */
- handle_ip_packet(iptr, dir);
+ iptr = (struct ip*) (packet + hdrlen); /* alignment? */
+ handle_ip_packet(iptr, dir, pkthdr->len - hdrlen);
}
}
@@ -648,7 +662,8 @@ static void handle_radiotap_packet(unsigned char* args, const struct pcap_pkthdr
{
/* 802.11 MAC header is = 34 bytes (not sure if that's universally true) */
/* We could try harder to figure out hardware direction from the MAC header */
- handle_ip_packet((struct ip*)(packet + ((struct radiotap_header *)packet)->it_len + 34),-1);
+ int hdrlen = ((struct radiotap_header *)packet)->it_len + 34;
+ handle_ip_packet((struct ip*)(packet + hdrlen), -1, pkthdr->len - hdrlen);
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-10-16 10:30:49 +0000