--- /dev/null
+/*
+ socketkiller a tool to kill off established tcp connections
+
+ Copyright (C) Ronnie Sahlberg 2007
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+#include "lib/events/events.h"
+#include "system/filesys.h"
+#include "system/network.h"
+#include "popt.h"
+#include "cmdline.h"
+#include "../include/ctdb.h"
+#include "../include/ctdb_private.h"
+#include <netinet/if_ether.h>
+
+/*
+ uint16 checksum for n bytes
+ */
+static uint32_t uint16_checksum(uint16_t *data, size_t n)
+{
+ uint32_t sum=0;
+ while (n>=2) {
+ sum += (uint32_t)ntohs(*data);
+ data++;
+ n -= 2;
+ }
+ if (n == 1) {
+ sum += (uint32_t)ntohs(*(uint8_t *)data);
+ }
+ return sum;
+}
+
+/*
+ simple TCP checksum - assumes data is multiple of 2 bytes long
+ */
+static uint16_t tcp_checksum(uint16_t *data, size_t n, struct iphdr *ip)
+{
+ uint32_t sum = uint16_checksum(data, n);
+ uint16_t sum2;
+ sum += uint16_checksum((uint16_t *)&ip->saddr, sizeof(ip->saddr));
+ sum += uint16_checksum((uint16_t *)&ip->daddr, sizeof(ip->daddr));
+ sum += ip->protocol + n;
+ sum = (sum & 0xFFFF) + (sum >> 16);
+ sum = (sum & 0xFFFF) + (sum >> 16);
+ sum2 = htons(sum);
+ sum2 = ~sum2;
+ if (sum2 == 0) {
+ return 0xFFFF;
+ }
+ return sum2;
+}
+
+int send_tcp(const struct sockaddr_in *dest, const struct sockaddr_in *src, uint32_t seq, uint32_t ack, int rst)
+{
+ int s, ret;
+ uint32_t one = 1;
+ struct {
+ struct iphdr ip;
+ struct tcphdr tcp;
+ } pkt;
+
+
+ /* for now, we only handle AF_INET addresses */
+ if (src->sin_family != AF_INET || dest->sin_family != AF_INET) {
+ DEBUG(0,(__location__ " not an ipv4 address\n"));
+ return -1;
+ }
+
+ s = socket(AF_INET, SOCK_RAW, htons(IPPROTO_RAW));
+ if (s == -1) {
+ DEBUG(0,(__location__ " failed to open raw socket (%s)\n",
+ strerror(errno)));
+ return -1;
+ }
+
+ ret = setsockopt(s, SOL_IP, IP_HDRINCL, &one, sizeof(one));
+ if (ret != 0) {
+ DEBUG(0,(__location__ " failed to setup IP headers (%s)\n",
+ strerror(errno)));
+ close(s);
+ return -1;
+ }
+
+ ZERO_STRUCT(pkt);
+ pkt.ip.version = 4;
+ pkt.ip.ihl = sizeof(pkt.ip)/4;
+ pkt.ip.tot_len = htons(sizeof(pkt));
+ pkt.ip.ttl = 255;
+ pkt.ip.protocol = IPPROTO_TCP;
+ pkt.ip.saddr = src->sin_addr.s_addr;
+ pkt.ip.daddr = dest->sin_addr.s_addr;
+ pkt.ip.check = 0;
+
+ pkt.tcp.source = src->sin_port;
+ pkt.tcp.dest = dest->sin_port;
+ pkt.tcp.seq = seq;
+ pkt.tcp.ack_seq = ack;
+ pkt.tcp.ack = 1;
+ if (rst) {
+ pkt.tcp.rst = 1;
+ }
+ pkt.tcp.doff = sizeof(pkt.tcp)/4;
+ pkt.tcp.window = htons(1234);
+ pkt.tcp.check = tcp_checksum((uint16_t *)&pkt.tcp, sizeof(pkt.tcp), &pkt.ip);
+
+ ret = sendto(s, &pkt, sizeof(pkt), 0, dest, sizeof(*dest));
+ if (ret != sizeof(pkt)) {
+ DEBUG(0,(__location__ " failed sendto (%s)\n", strerror(errno)));
+ close(s);
+ return -1;
+ }
+
+ close(s);
+ return 0;
+}
+
+
+void usage(void)
+{
+ printf("Usage: socketkiller <SRCIP> <SRCPORT> <DSTIP> <DSTPORT>\n");
+}
+
+int main(int argc, char *argv[])
+{
+ struct sockaddr_in src,dst;
+
+ if(argc!=5){
+ usage();
+ _exit(10);
+ }
+ int s, ret;
+#define RCVPKTSIZE 100
+ char pkt[RCVPKTSIZE];
+ struct ether_header *eth;
+ struct iphdr *ip;
+ struct tcphdr *tcp;
+
+ src.sin_family=AF_INET;
+ src.sin_port=htons(atoi(argv[2]));
+ inet_aton(argv[1], &src.sin_addr);
+
+ dst.sin_family=AF_INET;
+ dst.sin_port=htons(atoi(argv[4]));
+ inet_aton(argv[3], &dst.sin_addr);
+
+
+ /* wait for up to 5 seconds before giving up */
+ alarm(5);
+
+ s=socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
+
+ send_tcp(&dst, &src, 0, 0, 0);
+
+ while (1) {
+ ret = recv(s, pkt, RCVPKTSIZE, MSG_TRUNC);
+ if (ret<40) {
+ continue;
+ }
+
+ /* Ethernet */
+ eth = (struct ether_header *)pkt;
+ /* We only want IP packets */
+ if (ntohs(eth->ether_type) != ETHERTYPE_IP) {
+ continue;
+ }
+
+ /* IP */
+ ip = (struct iphdr *)&pkt[14];
+ /* We only want IPv4 packets */
+ if (ip->version != 4) {
+ continue;
+ }
+ /* Dont look at fragments */
+ if ((ntohs(ip->frag_off)&0x1fff) != 0) {
+ continue;
+ }
+ /* we only want TCP */
+ if (ip->protocol != IPPROTO_TCP) {
+ continue;
+ }
+
+ /* We only want packets sent from the guy we ticked */
+ if (ip->saddr != dst.sin_addr.s_addr) {
+ continue;
+ }
+ /* We only want packets sent to us */
+ if (ip->daddr != src.sin_addr.s_addr) {
+ continue;
+ }
+
+ /* TCP */
+ tcp = (struct tcphdr *)&pkt[14+ip->ihl*4];
+ /* We only want replies from the port we tickled */
+ if (tcp->source != dst.sin_port) {
+ continue;
+ }
+ if (tcp->dest != src.sin_port) {
+ continue;
+ }
+
+ printf("sending a RESET to tear down the connection\n");
+ send_tcp(&dst, &src, tcp->ack_seq, tcp->seq, 1);
+ close(s);
+ _exit(0);
+ }
+
+ close(s);
+ return 1;
+}
git.samba.org / sahlberg / ctdb.git / commitdiff