finished a first ping version (which still requires root)

4 files changed, 235 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index a33b419..83f8a68 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,8 @@ LIB = $(LIBUTF) $(LIBUTIL)
 BIN =\
 	more\
 	hexdump\
-	ifconfig
+	ifconfig\
+	ping
 
 LIBUTILOBJ = $(LIBUTILSRC:.c=.o)
 OBJ = $(BIN:=.o) $(LIBUTFOBJ) $(LIBUTILOBJ)
diff --git a/README b/README
index 24f0c06..99ae704 100644
--- a/README
+++ b/README
@@ -11,6 +11,8 @@ Currently it contains the following:
 - a 'ifconfig': show and configure simple interfaces
 - a 'ping': test a network connection
 - a 'netstat': see list of active connections of a machine
+- 'mkswap'
+- 'fsck.ext4', 'mkfs.ext4': if ext4 is the only file system we support
 
 Note: abase is a shameless copy of sbase/ubase in certain areas like
 the Makefile, libutil, etc. This might also make an integration into
@@ -48,5 +50,12 @@ Bugs and Questions
     - net-3-tools
     - nosh
   - netlink api or ioctls
-    
+
+References
+----------
+
+- ping:
+  - https://www.geeksforgeeks.org/ping-in-c/
+  - Stevens Network Programming, Vol. 1
+      
 [1] http://www.musl-libc.org/
diff --git a/ping.1 b/ping.1
new file mode 100644
index 0000000..c892f6f
--- /dev/null
+++ b/ping.1
@@ -0,0 +1,12 @@
+.Dd 2023-04-24
+.Dt PING 1
+.Os abase
+.Sh NAME
+.Nm ping
+.Nd tests reachability of a host on the network
+.Sh SYNOPSIS
+.Nm
+.Sh DESCRIPTION
+.Nm
+.Sh OPTIONS
+.sp
diff --git a/ping.c b/ping.c
new file mode 100644
index 0000000..2431d52
--- /dev/null
+++ b/ping.c
@@ -0,0 +1,211 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <netinet/ip_icmp.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <signal.h>
+#include <time.h>
+
+#include "util.h"
+
+static volatile int terminate = 0;
+
+static void
+usage(void)
+{
+	eprintf("usage: %s <destination>\n", argv0);
+}
+
+static void
+terminateHandler(int sig)
+{
+	terminate = 1;
+}
+
+/* as per RFC 1035 section 2.3.4 it is reasonable to assume host names
+ * are not longer than 255 characters */
+#define FQDN_LEN 255
+
+#define PING_PACKET_SIZE 64
+struct ping_packet {
+	struct icmphdr header;
+	char msg[PING_PACKET_SIZE-sizeof(struct icmphdr)];
+};
+
+/* see Stevens Unix Networking Programming Vol. 1, p. 672 */
+static
+unsigned short checksum(void *b, int buflen)
+{
+	unsigned short *buf = b;
+	unsigned int sum = 0;
+	unsigned short result = 0;
+
+	for (sum = 0; buflen > 1; buflen -= 2) {
+		sum += *buf++;
+	}
+	if (buflen == 1) {
+		sum += *(unsigned char*)buf;
+	}
+	sum = (sum >> 16) + (sum & 0xFFFF);
+	sum += (sum >>16);
+	result = ~sum;
+	
+	return result;
+}
+
+int
+main(int argc, char *argv[])
+{
+	struct addrinfo hints;
+	char *host;
+	struct addrinfo *addresses, *address;
+	struct sockaddr *ping_address;
+	struct sockaddr_in sending_address;
+	int res, fd;
+	struct timespec time_start, time_end;
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND
+	
+	if (argc != 1) {
+		weprintf("Expecting exactly one 'destination' to ping\n");
+		usage();
+	}
+	host = argv[0];
+	
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = AF_INET; /* IPv4 for now only */
+	hints.ai_socktype = SOCK_RAW;
+	hints.ai_flags = AI_CANONNAME;
+	hints.ai_protocol = IPPROTO_ICMP;
+	hints.ai_canonname = NULL;
+	hints.ai_addr = NULL;
+	hints.ai_next = NULL;
+	if ((res=getaddrinfo(host, NULL, &hints, &addresses)) != 0) {
+		weprintf("error calling getaddrinfo for '%s': %s\n", host, gai_strerror(res));
+		return 1;
+	}
+	
+	char ip_addr[INET_ADDRSTRLEN];
+	char canon_host[FQDN_LEN];
+	ping_address = NULL;
+	for (address = addresses; address != NULL; address = address->ai_next) {
+		struct sockaddr_in* addr = (struct sockaddr_in*)address->ai_addr;
+		inet_ntop(AF_INET, &addr->sin_addr, ip_addr, INET_ADDRSTRLEN);
+		strncpy(canon_host, address->ai_canonname, sizeof(canon_host));
+
+		fd = socket(address->ai_family, address->ai_socktype, address->ai_protocol);
+		if (fd == -1) {
+			if (errno == EPERM) {
+				weprintf("Permission denied, are you root?\n");
+				continue;
+			}
+			weprintf("socket failed: %s\n", strerror(errno));
+			continue;
+		} else {
+			ping_address = address->ai_addr;
+		}
+		
+		break;
+	}
+	
+	if (ping_address == NULL) {
+		return 1;
+	}
+	
+	signal(SIGINT, terminateHandler);
+	
+	printf("PING %s (%s)\n", canon_host, ip_addr);
+
+	int ttl_val = 255;
+	if (setsockopt(fd, SOL_IP, IP_TTL, &ttl_val, sizeof(ttl_val)) < 0) {
+		freeaddrinfo(addresses);
+		close(fd);
+		eprintf("Unable to set TTL on socket: %s\n", host, strerror(errno));
+	}
+
+	struct timeval tv_out;
+	tv_out.tv_sec = 1;
+	tv_out.tv_usec = 0;
+	if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv_out, sizeof(tv_out)) < 0) {
+		freeaddrinfo(addresses);
+		close(fd);
+		eprintf("Unable to set receive time on socket: %s\n", host, strerror(errno));
+	}
+	
+	int counter = 0;
+	int sent = 0;
+	int received = 0;
+	while (!terminate) {
+		struct ping_packet packet;
+		
+		memset(&packet, 0, sizeof(packet));
+		packet.header.type = ICMP_ECHO;
+		packet.header.code = 0; /* ECHO */
+		packet.header.un.echo.id = getpid();
+		packet.header.un.echo.sequence = counter;
+		for (int i = 0; i < sizeof(packet.msg)-1; i++) {
+			packet.msg[i] = counter+i;
+		}
+		packet.header.checksum = 0; /* set to 0 for checksum computation */
+		packet.header.checksum = checksum(&packet, sizeof(packet));
+		counter++;
+
+		sleep(1);
+
+		clock_gettime(CLOCK_MONOTONIC, &time_start);
+		
+		if (sendto(fd, &packet, sizeof(packet), 0, ping_address, sizeof(*ping_address)) < 0) {
+			weprintf("Unable to send packet to '%s': %s\n", host, strerror(errno));
+			sent = 0;
+		} else {
+			sent = 1;
+		}
+
+		int address_len = sizeof(sending_address);
+		if (recvfrom(fd, &packet, sizeof(packet), 0, (struct sockaddr *)&sending_address, &address_len) <= 0) {
+			freeaddrinfo(addresses);
+			close(fd);
+			eprintf("Unable to receive packet from '%s': %s\n", host, strerror(errno));			
+		} else {
+			if (sent) {
+				if (packet.header.type != 69 || packet.header.code != 0) {
+					freeaddrinfo(addresses);
+					close(fd);
+					eprintf("Received unknown ICMP package with code=%d and type=%d from '%s'",
+						packet.header.code, packet.header.type, host);
+				} else {
+					char sending_ip_addr[INET_ADDRSTRLEN];
+					//~ struct sockaddr_in* addr = (struct sockaddr_in*)&sending_address;
+					inet_ntop(AF_INET, &sending_address.sin_addr, ip_addr, INET_ADDRSTRLEN);
+
+					clock_gettime(CLOCK_MONOTONIC, &time_end);
+					double timeElapsed = ((double)(time_end.tv_nsec - time_start.tv_nsec)) / 1000000.0;
+					long double rtt_msec = (time_end.tv_sec - time_start.tv_sec) * 1000.0 + timeElapsed;
+
+					printf("%d bytes from %s (%s): icmp_seq=%d ttl=%d time=%0.3Lf ms\n",
+						sizeof(packet), host, ip_addr, counter, ttl_val, rtt_msec);
+					received++;
+				}
+			}
+		}
+	}
+	
+	printf("--- %s ping statistics ---\n"
+		"%d packets transmitted, %d received , %0.0f%% packet loss\n",
+		host, counter, received,
+		((counter - received)/counter) * 100.0); 
+
+	freeaddrinfo(addresses);
+	
+	close(fd);
+
+	return 0;
+}