first session work on project phase

project/.gitignore

@@ -0,0 +1 @@
+netem

project/Makefile

@@ -0,0 +1,17 @@
+TARGET = netem
+
+OBJS = main.o probe.o
+
+CC = gcc
+CFLAGS = -g -lrt
+
+all: $(TARGET) Makefile
+	
+$(TARGET): $(OBJS)
+	$(CC) -o $@ $^
+	
+clean:
+	rm -f $(TARGET)
+	rm -f *.o *~
+
+.PHONY: all clean

project/main.c

@@ -0,0 +1,98 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <errno.h>
+#include <error.h>
+
+#include <signal.h>
+#include <unistd.h>
+
+#define VERSION "0.1"
+
+int running = 1;
+
+void quit(int sig, siginfo_t *si, void *ptr)
+{
+	printf("Goodbye!\n");
+	running = 0;
+}
+
+int main(int argc, char *argv[])
+{
+	/* Options */
+	int mark;
+	int interval;
+	int rate;
+	
+	if (argc < 2) {
+		printf("usage: %s CMD [OPTIONS]\n", argv[0]);
+		printf("  CMD     can be one of:\n");
+		printf("    live          \n");
+		printf("    probe         \n");
+		printf("    emulate       \n");		
+		
+		/*
+		  -m --mark N                 apply emulation only to packet buffers with mark N
+		  -i --interval N             update the emulation parameters every N seconds
+		  -r --rate                   the packet rate used for measurements
+		*/
+		
+		printf("\n");
+		printf("netem util %s (built on %s %s)\n",
+			VERSION, __DATE__, __TIME__);
+		printf(" Copyright 2015, Steffen Vogel <post@steffenvogel.de>\n");
+
+		exit(EXIT_FAILURE);
+	}
+	
+	char *cmd = argv[1];
+
+	/* Setup signals */
+	struct sigaction sa_quit = {
+		.sa_flags = SA_SIGINFO,
+		.sa_sigaction = quit
+	};
+
+	sigemptyset(&sa_quit.sa_mask);
+	sigaction(SIGTERM, &sa_quit, NULL);
+	sigaction(SIGINT, &sa_quit, NULL);
+	
+	/* Parse Arguments */
+	char c, *endptr;
+	while ((c = getopt (argc-1, argv+1, "h:m:i:")) != -1) {
+		switch (c) {
+			case 'm':
+				mark = strtoul(optarg, &endptr, 10);
+				goto check;
+			case 'i':
+				interval = strtoul(optarg, &endptr, 10);
+				goto check;
+			case 'r':
+				rate = strtoul(optarg, &endptr, 10);
+				goto check;
+				
+			case '?':
+				if (optopt == 'c')
+					error(-1, 0, "Option -%c requires an argument.", optopt);
+				else if (isprint(optopt))
+					error(-1, 0, "Unknown option '-%c'.", optopt);
+				else
+					error(-1, 0, "Unknown option character '\\x%x'.", optopt);
+				exit(EXIT_FAILURE);
+			default:
+				abort();
+		}
+		
+		continue;
+check:
+		if (optarg == endptr)
+			error(-1, 0, "Failed to parse parse option argument '-%c %s'", c, optarg);
+	}
+
+	if (!strcmp(cmd, "probe"))
+		return probe();
+	else
+		error(-1, 0, "Unknown command: %s", cmd);
+	
+	return 0;
+}

project/probe.c

@@ -0,0 +1,60 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+int probe()
+{
+	int val;
+	
+	printf("Start probing\n");
+	
+	/* Create RAW socket */
+	int sd = socket(AF_INET, SOCK_RAW, IPPROTO_TCP);
+
+	/* Enable kernel / hw timestamping */
+	val  = SOF_TIMESTAMPING_RX_HARDWARE | SOF_TIMESTAMPING_RX_SOFTWARE;	/* Enable RX timestamps */
+	val |= SOF_TIMESTAMPING_TX_HARDWARE | SOF_TIMESTAMPING_TX_SOFTWARE;	/* Enable TX timestamps */
+	
+	val |= SOF_TIMESTAMPING_SOFTWARE | SOF_TIMESTAMPING_RAW_HARDWARE;	/* Report SW and HW timestamps */
+	
+	val |= SOF_TIMESTAMPING_OPT_TSONLY;					/* Only return timestamp in cmsg */
+
+	if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMPING, (void *) val, &val))
+		error(-1, errno, "Failed to set SO_TIMESTAMPING");
+	
+
+	return 0;
+}
+
+int probe_read_ts(int sd)
+{
+	char cmsg[1024];
+	struct msghdr msgh = {
+		.msg_name    = NULL,  .msg_namelen    = 0,
+		.msg_iov     = NULL,  .msg_iovlen     = 0,
+		.msg_control = &cmsg, .msg_controllen = sizeof(cmsg)
+	};
+	struct cmsghdr *cmsg;
+	struct timespec *ts;
+
+	if (recvmsg(sd, &msgh, 0) == -1)
+		error(-1, errno, "Failed to get control messages");
+
+	/* Receive auxiliary data in msgh */
+	for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg != NULL; cmsg = CMSG_NXTHDR(&msgh,cmsg)) {
+		if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_TIMESTAMPING) {
+			ts = (struct timespec*) CMSG_DATA(cmsg);
+			break;
+		}
+	}
+	if (cmsg == NULL)
+		error(-1, 0, "SO_TIMESTAMPING not enabled or small buffer or I/O error.");
+	
+	if (ts) {
+		for (int i = 0; i < 3; i++) {
+			print_ts(&ts[i]);
+		}
+	}
+}