aboutsummaryrefslogtreecommitdiffstats
path: root/src/icmp.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/icmp.c')
-rw-r--r--src/icmp.c359
1 files changed, 359 insertions, 0 deletions
diff --git a/src/icmp.c b/src/icmp.c
new file mode 100644
index 0000000..eb1ec5c
--- /dev/null
+++ b/src/icmp.c
@@ -0,0 +1,359 @@
+#include <errno.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <asm/types.h>
+#include <arpa/inet.h>
+#include <netinet/ip.h>
+#include <netinet/ip_icmp.h>
+
+#include "icmp.h"
+
+static char *pr_addr(__u32 addr)
+{
+ struct hostent *hp;
+ static char buf[4096];
+
+ sprintf(buf, "%s", inet_ntoa(*(struct in_addr *)&addr));
+ return buf;
+}
+
+static void pr_icmph(__u8 type, __u8 code, __u32 info, struct icmphdr *icp)
+{
+ switch (type) {
+ case ICMP_ECHOREPLY:
+ printf("Echo Reply\n");
+ /* XXX ID + Seq + Data */
+ break;
+ case ICMP_DEST_UNREACH:
+ switch(code) {
+ case ICMP_NET_UNREACH:
+ printf("Destination Net Unreachable\n");
+ break;
+ case ICMP_HOST_UNREACH:
+ printf("Destination Host Unreachable\n");
+ break;
+ case ICMP_PROT_UNREACH:
+ printf("Destination Protocol Unreachable\n");
+ break;
+ case ICMP_PORT_UNREACH:
+ printf("Destination Port Unreachable\n");
+ break;
+ case ICMP_FRAG_NEEDED:
+ printf("Frag needed and DF set (mtu = %u)\n", info);
+ break;
+ case ICMP_SR_FAILED:
+ printf("Source Route Failed\n");
+ break;
+ case ICMP_PKT_FILTERED:
+ printf("Packet filtered\n");
+ break;
+ default:
+ printf("Dest Unreachable, Bad Code: %d\n", code);
+ break;
+ }
+ break;
+ case ICMP_SOURCE_QUENCH:
+ printf("Source Quench\n");
+ break;
+ case ICMP_REDIRECT:
+ switch(code) {
+ case ICMP_REDIR_NET:
+ printf("Redirect Network");
+ break;
+ case ICMP_REDIR_HOST:
+ printf("Redirect Host");
+ break;
+ case ICMP_REDIR_NETTOS:
+ printf("Redirect Type of Service and Network");
+ break;
+ case ICMP_REDIR_HOSTTOS:
+ printf("Redirect Type of Service and Host");
+ break;
+ default:
+ printf("Redirect, Bad Code: %d", code);
+ break;
+ }
+ if (icp)
+ printf("(New nexthop: %s)\n", pr_addr(icp->un.gateway));
+ break;
+ case ICMP_ECHO:
+ printf("Echo Request\n");
+ /* XXX ID + Seq + Data */
+ break;
+ case ICMP_TIME_EXCEEDED:
+ switch(code) {
+ case ICMP_EXC_TTL:
+ printf("Time to live exceeded\n");
+ break;
+ case ICMP_EXC_FRAGTIME:
+ printf("Frag reassembly time exceeded\n");
+ break;
+ default:
+ printf("Time exceeded, Bad Code: %d\n", code);
+ break;
+ }
+ break;
+ case ICMP_PARAMETERPROB:
+ printf("Parameter problem: pointer = %u\n", icp ? (ntohl(icp->un.gateway)>>24) : info);
+ break;
+ case ICMP_TIMESTAMP:
+ printf("Timestamp\n");
+ /* XXX ID + Seq + 3 timestamps */
+ break;
+ case ICMP_TIMESTAMPREPLY:
+ printf("Timestamp Reply\n");
+ /* XXX ID + Seq + 3 timestamps */
+ break;
+ case ICMP_INFO_REQUEST:
+ printf("Information Request\n");
+ /* XXX ID + Seq */
+ break;
+ case ICMP_INFO_REPLY:
+ printf("Information Reply\n");
+ /* XXX ID + Seq */
+ break;
+#ifdef ICMP_MASKREQ
+ case ICMP_MASKREQ:
+ printf("Address Mask Request\n");
+ break;
+#endif
+#ifdef ICMP_MASKREPLY
+ case ICMP_MASKREPLY:
+ printf("Address Mask Reply\n");
+ break;
+#endif
+ default:
+ printf("Bad ICMP type: %d\n", type);
+ }
+}
+
+static u_short in_cksum(const u_short *addr, register int len, u_short csum)
+{
+ const u_short *w = addr;
+ u_short answer;
+ int sum = csum, nleft = len;
+
+ while (nleft > 1) {
+ sum += *w++;
+ nleft -= 2;
+ }
+
+ if (nleft == 1)
+ sum += htons(*(u_char *)w << 8);
+
+ sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
+ sum += (sum >> 16); /* add carry */
+ answer = ~sum; /* truncate to 16 bits */
+
+ return answer;
+}
+
+
+int icmp_parse_reply(__u8 *buf, int len, int seq,
+ struct sockaddr *addr,
+ struct sockaddr *origdest)
+{
+ struct sockaddr_in *from = (struct sockaddr_in *) addr;
+ struct sockaddr_in *to = (struct sockaddr_in *) origdest;
+ struct icmphdr *icp;
+ struct iphdr *ip;
+ int hlen, csfailed;
+
+ /* Check the IP header */
+ ip = (struct iphdr *) buf;
+ hlen = ip->ihl * 4;
+ if (len < hlen + 8 || ip->ihl < 5)
+ return 1;
+
+ /* Now the ICMP part */
+ len -= hlen;
+ icp = (struct icmphdr *)(buf + hlen);
+ csfailed = in_cksum((u_short *)icp, len, 0);
+
+ if (icp->type == ICMP_ECHOREPLY) {
+ if (icp->un.echo.id != getpid() ||
+ ntohs(icp->un.echo.sequence) != seq)
+ return 1; /* 'Twas not our ECHO */
+
+ printf("From %s: icmp_seq=%u bytes=%d\n",
+ pr_addr(from->sin_addr.s_addr),
+ ntohs(icp->un.echo.sequence), len);
+ } else {
+ /* We fall here when a redirect or source quench arrived.
+ * Also this branch processes icmp errors, when IP_RECVERR
+ * is broken. */
+
+ switch (icp->type) {
+ case ICMP_ECHO:
+ /* MUST NOT */
+ return 1;
+ case ICMP_SOURCE_QUENCH:
+ case ICMP_REDIRECT:
+ case ICMP_DEST_UNREACH:
+ case ICMP_TIME_EXCEEDED:
+ case ICMP_PARAMETERPROB:
+ {
+ struct iphdr * iph = (struct iphdr *)(&icp[1]);
+ struct icmphdr *icp1 = (struct icmphdr*)((unsigned char *)iph + iph->ihl*4);
+ int error_pkt;
+ if (len < 8 + sizeof(struct iphdr) + 8 ||
+ len < 8 + iph->ihl * 4 + 8)
+ return 1;
+ if (icp1->type != ICMP_ECHO ||
+ iph->daddr != to->sin_addr.s_addr ||
+ icp1->un.echo.id != getpid() ||
+ ntohs(icp1->un.echo.sequence) != seq)
+ return 1;
+ error_pkt = (icp->type != ICMP_REDIRECT &&
+ icp->type != ICMP_SOURCE_QUENCH);
+ if (error_pkt) {
+ //acknowledge(ntohs(icp1->un.echo.sequence));
+ }
+
+ printf("From %s: icmp_seq=%u ",
+ pr_addr(from->sin_addr.s_addr),
+ ntohs(icp1->un.echo.sequence));
+ if (csfailed)
+ printf("(BAD CHECKSUM)");
+ pr_icmph(icp->type, icp->code, ntohl(icp->un.gateway), icp);
+ return !error_pkt;
+ }
+ default:
+ /* MUST NOT */
+ break;
+ }
+ printf("From %s: ", pr_addr(from->sin_addr.s_addr));
+ pr_icmph(icp->type, icp->code, ntohl(icp->un.gateway), icp);
+ return 0;
+ }
+
+ return 0;
+}
+
+int icmp_send(int fd, struct sockaddr *to, int tolen, void *buf, int buflen)
+{
+ int i;
+
+ i = sendto(fd, buf, buflen, 0, to, tolen);
+ if (i != buflen)
+ return -1;
+
+ return 0;
+}
+
+int icmp_send_frag_needed(int fd, struct sockaddr *to, int tolen,
+ struct iphdr *iph, int newmtu)
+{
+ struct sockaddr_in *to_in = (struct sockaddr_in *) to;
+ const int len = sizeof(struct icmphdr) + sizeof(struct iphdr) + 8;
+ char packet[len];
+ struct icmphdr *icp;
+
+ icp = (struct icmphdr *) packet;
+ icp->type = ICMP_DEST_UNREACH;
+ icp->code = ICMP_FRAG_NEEDED;
+ icp->checksum = 0;
+ icp->un.frag.__unused = 0;
+ icp->un.frag.mtu = htons(newmtu);
+
+ /* copy ip header + 64-bits of original packet */
+ memcpy(icp + 1, iph, sizeof(struct iphdr) + 8);
+
+ icp->checksum = in_cksum((u_short *) icp, len, 0);
+
+ printf("To %s: frag_needed mtu=%d\n",
+ pr_addr(to_in->sin_addr.s_addr), newmtu);
+
+ return icmp_send(fd, to, tolen, packet, len);
+}
+
+int icmp_send_ping(int fd, struct sockaddr *to, int tolen,
+ int seq, int total_size)
+{
+ struct sockaddr_in *to_in = (struct sockaddr_in *) to;
+ __u8 packet[1500];
+ struct icmphdr *icp;
+ int len;
+
+ if (total_size > sizeof(packet))
+ return -1;
+ if (total_size < sizeof(struct iphdr) + sizeof(struct icmphdr))
+ total_size = sizeof(struct iphdr) + sizeof(struct icmphdr);
+
+ len = total_size - sizeof(struct iphdr);
+ memset(packet, 0, sizeof(packet));
+
+ icp = (struct icmphdr *) packet;
+ icp->type = ICMP_ECHO;
+ icp->code = 0;
+ icp->checksum = 0;
+ icp->un.echo.sequence = htons(seq);
+ icp->un.echo.id = getpid();
+ icp->checksum = in_cksum((u_short *) icp, len, 0);
+#if 0
+ printf("To %s: icmp_seq=%u bytes=%d\n",
+ pr_addr(to_in->sin_addr.s_addr), seq, len);
+#endif
+ return icmp_send(fd, to, tolen, (void *) packet, len);
+}
+
+int icmp_read_reply(int fd, struct sockaddr *from, int fromlen,
+ __u8 *buf, int buflen)
+{
+ struct iovec iov;
+ int len;
+
+ len = recvfrom(fd, buf, buflen, 0, from, &fromlen);
+ if (len < 0) {
+ if (errno == EAGAIN || errno == EINTR)
+ return 0;
+ return -1;
+ }
+
+ return len;
+}
+
+int icmp_open(float timeout)
+{
+ const int pmtudisc = IP_PMTUDISC_DO, yes = 1;
+ struct timeval tv;
+ int fd;
+
+ fd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
+ if (fd < 0) {
+ perror("mtuinject: socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)");
+ goto err;
+ }
+
+ if (setsockopt(fd, SOL_IP, IP_MTU_DISCOVER,
+ &pmtudisc, sizeof(pmtudisc)) == -1) {
+ perror("ping: IP_MTU_DISCOVER");
+ goto err_close;
+ }
+
+ tv.tv_sec = (time_t) timeout;
+ tv.tv_usec = (timeout - tv.tv_sec) * 1000000;
+ setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, (char*)&tv, sizeof(tv));
+
+ tv.tv_sec = (time_t) timeout;
+ tv.tv_usec = (timeout - tv.tv_sec) * 1000000;
+ if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO,
+ (char*)&tv, sizeof(tv)) == -1)
+ goto err_close;
+
+ return fd;
+
+err_close:
+ close(fd);
+err:
+ return -1;
+}
+
+void icmp_close(int fd)
+{
+ close(fd);
+}
+
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-18 17:47:04 +0000