Date: Wed, 14 May 2008 21:38:37 GMT From: Rui Paulo <rpaulo@FreeBSD.org> To: Perforce Change Reviews <perforce@FreeBSD.org> Subject: PERFORCE change 141607 for review Message-ID: <200805142138.m4ELcbGO048587@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=141607 Change 141607 by rpaulo@rpaulo_epsilon on 2008/05/14 21:38:02 Add initial processing of the 3WHS. Affected files ... .. //depot/projects/soc2008/rpaulo-tcpad/handler.c#2 edit .. //depot/projects/soc2008/rpaulo-tcpad/main.c#3 edit .. //depot/projects/soc2008/rpaulo-tcpad/tcpad.h#1 add Differences ... ==== //depot/projects/soc2008/rpaulo-tcpad/handler.c#2 (text+ko) ==== @@ -23,52 +23,144 @@ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * - * $P4: //depot/projects/soc2008/rpaulo-tcpad/handler.c#1 $ + * $P4: //depot/projects/soc2008/rpaulo-tcpad/handler.c#2 $ */ #include <stdio.h> +#include <stdlib.h> +#include <string.h> #include <sys/socket.h> +#include <sys/queue.h> #include <netinet/in.h> #include <netinet/ip.h> #include <netinet/tcp.h> +#include <netinet/tcp_fsm.h> #include <arpa/inet.h> #include <pcap.h> +#include "tcpad.h" #include "linkhdr.h" #include "handler.h" #include "debug.h" + +static conn_t * find_conn(struct in_addr ipsrc, struct in_addr ipdst, + unsigned short sport, unsigned short dport); +static void print_packet(const unsigned char *bytes, const int linkhlen); + void -tcpad_pcaphandler(unsigned char *user __unused, - const struct pcap_pkthdr *h __unused, +tcpad_pcaphandler(unsigned char *user, const struct pcap_pkthdr *h __unused, const unsigned char *bytes) { const struct ip *ip; const struct tcphdr *tcp; + int linkhlen; + conn_t *cp; + + linkhlen = (int)*user; - ip = (const struct ip *)linkhdr_remove(bytes, 4); + ip = (const struct ip *)linkhdr_remove(bytes, linkhlen); tcp = (const struct tcphdr *)linkhdr_remove(bytes, - 4 + sizeof(struct ip)); + linkhlen + sizeof(struct ip)); + + cp = find_conn(ip->ip_src, ip->ip_dst, tcp->th_sport, + tcp->th_dport); + if ((tcp->th_flags & TH_FLAGS) == TH_SYN) { + if (cp) { + DPRINTF("connection already being tracked!\n"); + print_packet(bytes, linkhlen); + LIST_REMOVE(cp, entries); + free(cp); + } + cp = malloc(sizeof(*cp)); + cp->tcpstate = TCPS_SYN_SENT; + cp->dport = tcp->th_dport; + cp->sport = tcp->th_sport; + cp->isv6 = 0; + memcpy(&cp->sv4addr, &ip->ip_src, sizeof(struct in_addr)); + memcpy(&cp->dv4addr, &ip->ip_dst, sizeof(struct in_addr)); + DPRINTF("tracking connection (syn) between %s and %s\n", + inet_ntoa(cp->sv4addr), inet_ntoa(cp->dv4addr)); + LIST_INSERT_HEAD(&chead, cp, entries); + print_packet(bytes, linkhlen); + } else if ((tcp->th_flags & TH_FLAGS) == (TH_SYN|TH_ACK)) { + if (cp) { + DPRINTF("connection already being tracked!\n"); + print_packet(bytes, linkhlen); + LIST_REMOVE(cp, entries); + free(cp); + } + cp = malloc(sizeof(*cp)); + cp->tcpstate = TCPAD_SYN_RECEIVED; + cp->dport = tcp->th_dport; + cp->sport = tcp->th_sport; + cp->isv6 = 0; + memcpy(&cp->sv4addr, &ip->ip_src, sizeof(struct in_addr)); + memcpy(&cp->dv4addr, &ip->ip_dst, sizeof(struct in_addr)); + DPRINTF("tracking connection (syn/ack) between %s and %s\n", + inet_ntoa(cp->sv4addr), inet_ntoa(cp->dv4addr)); + LIST_INSERT_HEAD(&chead, cp, entries); + print_packet(bytes, linkhlen); + } else if ((tcp->th_flags & TH_FLAGS) == TH_ACK) { + + } else if ((tcp->th_flags & TH_FLAGS) == TH_RST || + (tcp->th_flags & TH_FLAGS) == TH_FIN) { + if (!cp) { + DPRINTF("connection not found, ignoring\n"); + print_packet(bytes, linkhlen); + } + DPRINTF("removing connection\n"); + print_packet(bytes, linkhlen); + LIST_REMOVE(cp, entries); + free(cp); + } +} + +static conn_t * +find_conn(struct in_addr ipsrc, struct in_addr ipdst, unsigned short + sport, unsigned short dport) +{ + conn_t *cp; + + LIST_FOREACH(cp, &chead, entries) { + if (memcmp(&cp->sv4addr, &ipsrc, sizeof(struct in_addr)) && + memcmp(&cp->dv4addr, &ipdst, sizeof(struct in_addr)) && + cp->sport == sport && cp->dport == dport) + return (cp); + } + + return (NULL); +} - DPRINTF("IP (tos 0x%x, ttl %d, id %d, offset %d, flags XX, " - "proto TCP (%d), length %d) %s.%d > %s.%d: ", ip->ip_tos, - ip->ip_ttl, htons(ip->ip_id), ip->ip_off, ip->ip_p, - htons(ip->ip_len), inet_ntoa(ip->ip_src), tcp->th_sport, - inet_ntoa(ip->ip_dst), tcp->th_dport); +static void +print_packet(const unsigned char *bytes, const int linkhlen) +{ + const struct ip *ip; + const struct tcphdr *tcp; + + ip = (const struct ip *)linkhdr_remove(bytes, linkhlen); + tcp = (const struct tcphdr *)linkhdr_remove(bytes, + linkhlen + sizeof(struct ip)); + printf("IP (tos 0x%x, ttl %d, id %d, offset %d, flags XX, " + "proto TCP (%d), length %d) %s.%d > %s.%d: ", ip->ip_tos, + ip->ip_ttl, htons(ip->ip_id), ip->ip_off, ip->ip_p, + htons(ip->ip_len), inet_ntoa(ip->ip_src), tcp->th_sport, + inet_ntoa(ip->ip_dst), tcp->th_dport); + if (tcp->th_flags & TH_FIN) - DPRINTF("F"); + printf("F"); if (tcp->th_flags & TH_SYN) - DPRINTF("S"); + printf("S"); if (tcp->th_flags & TH_RST) - DPRINTF("R"); + printf("R"); if (tcp->th_flags & TH_ACK) - DPRINTF("."); + printf("."); if (tcp->th_flags & TH_URG) - DPRINTF("U"); + printf("U"); if (tcp->th_flags & TH_PUSH) - DPRINTF("P"); + printf("P"); if (tcp->th_flags & TH_ECE) - DPRINTF("E"); - DPRINTF("\n"); + printf("E"); + printf("\n"); } ==== //depot/projects/soc2008/rpaulo-tcpad/main.c#3 (text+ko) ==== @@ -23,7 +23,7 @@ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * - * $P4: //depot/projects/soc2008/rpaulo-tcpad/main.c#2 $ + * $P4: //depot/projects/soc2008/rpaulo-tcpad/main.c#3 $ */ #include <err.h> @@ -31,7 +31,9 @@ #include <stdlib.h> #include <unistd.h> #include <pcap.h> +#include <sys/queue.h> +#include "tcpad.h" #include "device.h" #include "linkhdr.h" #include "handler.h" @@ -56,6 +58,7 @@ pcap_t *p; struct bpf_program fp; char filter[] = "ip proto \\tcp"; + int linkhlen; promisc = 1; snaplen = 100; @@ -96,8 +99,13 @@ errx(1, "pcap_compile: %s", pcap_geterr(p)); pcap_setfilter(p, &fp); + linkhlen = linkhdr_headerlen(pcap_datalink(p)); + if (linkhlen == -1) + errx(1, "interface type not recognized"); + LIST_INIT(&chead); for (;;) { - pcap_dispatch(p, -1, tcpad_pcaphandler, NULL); + pcap_dispatch(p, -1, tcpad_pcaphandler, + (unsigned char *)&linkhlen); } }
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