2:34 a.m.
Intent is to minimize number of passed arguments to getpacket(),
adjustpacket() and processpacket().
I made new functions packet_get(), packet_adjust() and packet_process()
which copy functionality of their counterparts but they do it
on struct pkt_hdr.
After converting all uses of getpacket() etc. to packet_get() we
can remove the old ones (getpacket(), processpacket() and
adjustpacket()).
Signed-off-by: Vitezslav Samel <vitezslav(a)samel.cz>
---
src/packet.c | 258 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/packet.h | 25 ++++++
2 files changed, 283 insertions(+), 0 deletions(-)
diff --git a/src/packet.c b/src/packet.c
index e65f879..df70428 100644
--- a/src/packet.c
+++ b/src/packet.c
@@ -129,6 +129,65 @@ static void adjustpacket(char *tpacket, struct sockaddr_ll
*fromaddr,
} /* to the caller. Hopefully, this */
} /* switch statement will grow. */
+static int packet_adjust(struct pkt_hdr *pkt)
+{
+ int retval = 0;
+
+ switch (pkt->pkt_hatype) {
+ case ARPHRD_ETHER:
+ case ARPHRD_LOOPBACK:
+ pkt->pkt_payload = pkt->pkt_buf;
+ pkt->pkt_payload += ETH_HLEN;
+ pkt->pkt_len -= ETH_HLEN;
+ if (pkt->pkt_protocol == ETH_P_8021Q) {
+ /* strip 0x8100 802.1Q VLAN Extended Header */
+ pkt->pkt_payload += 4;
+ pkt->pkt_len -= 4;
+ /* update network protocol */
+ pkt->pkt_protocol = ntohs(*((unsigned short *) pkt->pkt_payload));
+ }
+ break;
+ case ARPHRD_SLIP:
+ case ARPHRD_CSLIP:
+ case ARPHRD_SLIP6:
+ case ARPHRD_PPP:
+ case ARPHRD_CSLIP6:
+ case ARPHRD_TUNNEL:
+ case ARPHRD_NONE:
+ case ARPHRD_IPGRE:
+ pkt->pkt_payload = pkt->pkt_buf;
+ break;
+ case ARPHRD_FRAD:
+ case ARPHRD_DLCI:
+ pkt->pkt_payload = pkt->pkt_buf;
+ pkt->pkt_payload += 4;
+ pkt->pkt_len -= 4;
+ break;
+ case ARPHRD_FDDI:
+ pkt->pkt_payload = pkt->pkt_buf;
+ pkt->pkt_payload += sizeof(struct fddihdr);
+ pkt->pkt_len -= sizeof(struct fddihdr);
+ break;
+ case ARPHRD_IEEE802_TR:
+ case ARPHRD_IEEE802:
+ pkt->pkt_payload = pkt->pkt_buf;
+ /* Token Ring patch supplied by Tomas Dvorak */
+ /* Get the start of the IP packet from the Token Ring frame. */
+ unsigned int dataoffset = get_tr_ip_offset(pkt->pkt_payload);
+ pkt->pkt_payload += dataoffset;
+ pkt->pkt_len -= dataoffset;
+ break;
+ default:
+ /* return a NULL packet to signal an unrecognized link */
+ /* protocol to the caller. Hopefully, this switch statement */
+ /* will grow. */
+ pkt->pkt_payload = (char *) NULL;
+ retval = -1;
+ break;
+ }
+ return retval;
+}
+
/*
* IPTraf input function; reads both keystrokes and network packets.
*/
@@ -170,6 +229,56 @@ void getpacket(int fd, char *buf, struct sockaddr_ll *fromaddr, int
*ch,
*ch = wgetch(win);
}
+/* IPTraf input function; reads both keystrokes and network packets. */
+void packet_get(int fd, struct pkt_hdr *pkt, int *ch, WINDOW *win)
+{
+ fd_set set;
+ int ss;
+
+ do {
+ FD_ZERO(&set);
+
+ /* Monitor stdin only if in interactive, not daemon mode. */
+ if (!daemonized)
+ FD_SET(0, &set);
+
+ /* Monitor raw socket */
+ FD_SET(fd, &set);
+
+ struct timeval tv = {
+ .tv_sec = 0,
+ .tv_usec = DEFAULT_UPDATE_DELAY
+ };
+
+ ss = select(fd + 1, &set, 0, 0, &tv);
+ } while ((ss < 0) && (errno == EINTR));
+
+ *ch = ERR;
+
+ if (FD_ISSET(fd, &set)) {
+ struct sockaddr_ll from;
+ socklen_t fromlen = sizeof(struct sockaddr_ll);
+ ssize_t len;
+
+ len = recvfrom(fd, pkt->pkt_buf, pkt->pkt_bufsize, MSG_TRUNC,
+ (struct sockaddr *) &from, &fromlen);
+ if (len > 0) {
+ pkt->pkt_len = len;
+ pkt->pkt_caplen = len;
+ if (pkt->pkt_caplen > pkt->pkt_bufsize)
+ pkt->pkt_caplen = pkt->pkt_bufsize;
+ pkt->pkt_payload = NULL;
+ pkt->pkt_protocol = ntohs(from.sll_protocol);
+ pkt->pkt_ifindex = from.sll_ifindex;
+ pkt->pkt_hatype = from.sll_hatype;
+ pkt->pkt_pkttype = from.sll_pkttype;
+ } else
+ pkt->pkt_len = 0;
+ }
+ if (!daemonized && FD_ISSET(0, &set))
+ *ch = wgetch(win);
+}
+
int processpacket(char *tpacket, char **packet, unsigned int *br,
unsigned int *total_br, unsigned int *sport,
unsigned int *dport, struct sockaddr_ll *fromaddr,
@@ -326,6 +435,155 @@ again: if (fromaddr->sll_protocol == ETH_P_IP) {
return PACKET_OK;
}
+int packet_process(struct pkt_hdr *pkt, unsigned int *total_br,
+ unsigned int *sport, unsigned int *dport,
+ struct filterstate *filter, int match_opposite,
+ int v6inv4asv6)
+{
+ /* move packet pointer (pkt->pkt_payload) past data link header */
+ if (packet_adjust(pkt) != 0)
+ return INVALID_PACKET;
+
+again: if (pkt->pkt_protocol == ETH_P_IP) {
+ struct iphdr *ip;
+ int hdr_check;
+ register int ip_checksum;
+ register int iphlen;
+ unsigned int f_sport = 0, f_dport = 0;
+
+ /*
+ * At this point, we're now processing IP packets. Start by getting
+ * IP header and length.
+ */
+ ip = (struct iphdr *) (pkt->pkt_payload);
+ iphlen = ip->ihl * 4;
+
+ /*
+ * Compute and verify IP header checksum.
+ */
+
+ ip_checksum = ip->check;
+ ip->check = 0;
+ hdr_check = in_cksum((u_short *) ip, iphlen);
+
+ if ((hdr_check != ip_checksum))
+ return CHECKSUM_ERROR;
+
+ if ((ip->protocol == IPPROTO_TCP || ip->protocol == IPPROTO_UDP)
+ && (sport != NULL && dport != NULL)) {
+ unsigned int sport_tmp, dport_tmp;
+
+ /*
+ * Process TCP/UDP fragments
+ */
+ if ((ntohs(ip->frag_off) & 0x3fff) != 0) {
+ int firstin;
+
+ /*
+ * total_br contains total byte count of all fragments
+ * not yet retrieved. Will differ only if fragments
+ * arrived before the first fragment, in which case
+ * the total accumulated fragment sizes will be returned
+ * once the first fragment arrives.
+ */
+
+ if (total_br != NULL)
+ *total_br =
+ processfragment(ip, &sport_tmp,
+ &dport_tmp,
+ &firstin);
+
+ if (!firstin)
+ return MORE_FRAGMENTS;
+ } else {
+ struct tcphdr *tcp;
+ struct udphdr *udp;
+ char *ip_payload = (char *) ip + iphlen;
+
+ switch (ip->protocol) {
+ case IPPROTO_TCP:
+ tcp = (struct tcphdr *) ip_payload;
+ sport_tmp = tcp->source;
+ dport_tmp = tcp->dest;
+ break;
+ case IPPROTO_UDP:
+ udp = (struct udphdr *) ip_payload;
+ sport_tmp = udp->source;
+ dport_tmp = udp->dest;
+ break;
+ default:
+ sport_tmp = 0;
+ dport_tmp = 0;
+ break;
+ }
+
+ if (total_br != NULL)
+ *total_br = pkt->pkt_len;
+ }
+
+ if (sport != NULL)
+ *sport = sport_tmp;
+
+ if (dport != NULL)
+ *dport = dport_tmp;
+
+ /*
+ * Process IP filter
+ */
+ f_sport = ntohs(sport_tmp);
+ f_dport = ntohs(dport_tmp);
+ }
+ if ((filter->filtercode != 0)
+ &&
+ (!ipfilter
+ (ip->saddr, ip->daddr, f_sport, f_dport, ip->protocol,
+ match_opposite, &(filter->fl))))
+ return PACKET_FILTERED;
+ if (v6inv4asv6 && (ip->protocol == IPPROTO_IPV6)) {
+ pkt->pkt_protocol = ETH_P_IPV6;
+ pkt->pkt_payload += iphlen;
+ pkt->pkt_len -= iphlen;
+ goto again;
+ }
+ return PACKET_OK;
+ } else if (pkt->pkt_protocol == ETH_P_IPV6) {
+ struct tcphdr *tcp;
+ struct udphdr *udp;
+ struct ip6_hdr *ip6 = (struct ip6_hdr *) pkt->pkt_payload;
+ char *ip_payload = (char *) ip6 + 40;
+
+ //TODO: Filter packets
+ switch (ip6->ip6_nxt) { /* FIXME: extension headers ??? */
+ case IPPROTO_TCP:
+ tcp = (struct tcphdr *) ip_payload;
+ if (sport)
+ *sport = tcp->source;
+ if (dport)
+ *dport = tcp->dest;
+ break;
+ case IPPROTO_UDP:
+ udp = (struct udphdr *) ip_payload;
+ if (sport)
+ *sport = udp->source;
+ if (dport)
+ *dport = udp->dest;
+ break;
+ default:
+ if (sport)
+ *sport = 0;
+ if (dport)
+ *dport = 0;
+ break;
+ }
+ } else {
+ /* not IPv4 and not IPv6: apply non-IP packet filter */
+ if (!nonipfilter(filter, pkt->pkt_protocol)) {
+ return PACKET_FILTERED;
+ }
+ }
+ return PACKET_OK;
+}
+
void pkt_cleanup(void)
{
// close(isdnfd);
diff --git a/src/packet.h b/src/packet.h
index bdf1d0d..5a23ff5 100644
--- a/src/packet.h
+++ b/src/packet.h
@@ -25,14 +25,39 @@ Written by Gerard Paul Java
extern int isdnfd;
+struct pkt_hdr {
+ char pkt_buf[MAX_PACKET_SIZE];
+ size_t pkt_bufsize;
+ char *pkt_payload;
+ size_t pkt_caplen; /* bytes captured */
+ size_t pkt_len; /* bytes on-the-wire */
+ unsigned short pkt_protocol; /* Physical layer protocol: ETH_P_* */
+ int pkt_ifindex; /* Interface number */
+ unsigned short pkt_hatype; /* Header type: ARPHRD_* */
+ unsigned char pkt_pkttype; /* Packet type: PACKET_OUTGOING, PACKET_BROADCAST, ... */
+ unsigned char pkt_halen; /* Length of address */
+ unsigned char pkt_addr[8]; /* Physical layer address */
+};
+
+#define PACKET_INIT(packet) \
+ struct pkt_hdr packet = { \
+ .pkt_bufsize = MAX_PACKET_SIZE, \
+ .pkt_payload = NULL \
+ };
+
void open_socket(int *fd);
void getpacket(int fd, char *buf, struct sockaddr_ll *fromaddr, int *ch,
int *br, WINDOW * win);
+void packet_get(int fd, struct pkt_hdr *pkt, int *ch, WINDOW *win);
int processpacket(char *tpacket, char **packet, unsigned int *br,
unsigned int *total_br, unsigned int *sport,
unsigned int *dport, struct sockaddr_ll *fromaddr,
struct filterstate *ofilter,
int match_opposite, int v6inv4asv6);
+int packet_process(struct pkt_hdr *pkt, unsigned int *total_br,
+ unsigned int *sport, unsigned int *dport,
+ struct filterstate *filter, int match_opposite,
+ int v6inv4asv6);
void pkt_cleanup(void);
#endif /* IPTRAF_NG_PACKET_H */
--
1.7.8.4