irq: break out from xutils and save + restore

Break out IRQ functionality from xutils, simplify it, and
save + restore IRQ affinity list.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

8 files changed, 145 insertions, 112 deletions

diff --git a/irq.c b/irq.c
new file mode 100644
index 0000000..fbd1cbc
--- /dev/null
+++ b/irq.c
@@ -0,0 +1,129 @@
+/*
+ * netsniff-ng - the packet sniffing beast
+ * Copyright 2009 - 2013 Daniel Borkmann.
+ * Copyright 2009, 2010 Emmanuel Roullit.
+ * Subject to the GPL, version 2.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "irq.h"
+#include "die.h"
+#include "xutils.h"
+
+int device_irq_number(const char *ifname)
+{
+	int irq = 0;
+	char buff[128], sysname[128];
+	FILE *fp;
+
+	if (!strncmp("lo", ifname, strlen("lo")))
+		return 0;
+
+	slprintf(sysname, sizeof(sysname),
+		 "/sys/class/net/%s/device/irq",
+		 ifname);
+
+	fp = fopen(sysname, "r");
+	if (!fp)
+		return -ENOENT;
+
+	memset(buff, 0, sizeof(buff));
+
+	if (fgets(buff, sizeof(buff), fp) != NULL) {
+		buff[sizeof(buff) - 1] = 0;
+		irq = atoi(buff);
+	}
+
+	fclose(fp);
+	return irq;
+}
+
+static char nic_irq_affinity_list[128];
+static bool nic_irq_stored = false;
+static int  nic_irq = -1;
+
+static void device_save_irq_affinity_list(void)
+{
+	int ret, fd;
+	char file[128];
+
+	bug_on(nic_irq_stored);
+
+	slprintf(file, sizeof(file),
+		 "/proc/irq/%d/smp_affinity_list", nic_irq);
+
+	fd = open(file, O_RDONLY);
+	if (fd < 0)
+		return;
+
+	memset(nic_irq_affinity_list, 0, sizeof(nic_irq_affinity_list));
+
+	ret = read(fd, nic_irq_affinity_list,
+		   sizeof(nic_irq_affinity_list));
+	if (ret < 0)
+		panic("Cannot store NIC IRQ affinity!\n");
+
+	close(fd);
+
+	nic_irq_stored = true;
+}
+
+void device_restore_irq_affinity_list(void)
+{
+	int ret, fd;
+	char file[128];
+
+	if (!nic_irq_stored)
+		return;
+
+	bug_on(nic_irq == -1);
+
+	slprintf(file, sizeof(file),
+		 "/proc/irq/%d/smp_affinity_list", nic_irq);
+
+	fd = open(file, O_WRONLY);
+	if (fd < 0)
+		return;
+
+	ret = write(fd, nic_irq_affinity_list,
+		    sizeof(nic_irq_affinity_list));
+	if (ret < 0)
+		panic("Cannot restore NIC IRQ affinity!\n");
+
+	close(fd);
+}
+
+int device_set_irq_affinity_list(int irq, unsigned long from, unsigned long to)
+{
+	int ret, fd;
+	char file[128], list[64];
+
+	if (!nic_irq_stored) {
+		nic_irq = irq;
+		device_save_irq_affinity_list();
+	}
+
+	slprintf(file, sizeof(file), "/proc/irq/%d/smp_affinity_list", irq);
+	slprintf(list, sizeof(list), "%lu-%lu\n", from, to);
+
+	fd = open(file, O_WRONLY);
+	if (fd < 0)
+		return -ENOENT;
+
+	ret = write(fd, list, strlen(list));
+
+	close(fd);
+	return ret;
+}
+
+int device_bind_irq_to_cpu(int irq, int cpu)
+{
+	return device_set_irq_affinity_list(irq, cpu, cpu);
+}
diff --git a/irq.h b/irq.h
new file mode 100644
index 0000000..6c1c850
--- /dev/null
+++ b/irq.h
@@ -0,0 +1,10 @@
+#ifndef IRQ_H
+#define IRQ_H
+
+extern int device_irq_number(const char *ifname);
+extern int device_bind_irq_to_cpu(int irq, int cpu);
+extern void device_restore_irq_affinity_list(void);
+extern int device_set_irq_affinity_list(int irq, unsigned long from,
+					unsigned long to);
+
+#endif /* IRQ_H */
diff --git a/netsniff-ng.c b/netsniff-ng.c
index 4d9abc8..899a148 100644
--- a/netsniff-ng.c
+++ b/netsniff-ng.c
@@ -32,6 +32,7 @@
 #include "bpf.h"
 #include "xio.h"
 #include "die.h"
+#include "irq.h"
 #include "geoip.h"
 #include "tprintf.h"
 #include "dissector.h"
@@ -1398,7 +1399,7 @@ int main(int argc, char **argv)
 	if (setsockmem)
 		reset_system_socket_memory(vals, array_size(vals));
 	destroy_geoip();
-
+	device_restore_irq_affinity_list();
 	tprintf_cleanup();
 
 	free(ctx.device_in);
diff --git a/netsniff-ng/Makefile b/netsniff-ng/Makefile
index 211c726..7d5f89c 100644
--- a/netsniff-ng/Makefile
+++ b/netsniff-ng/Makefile
@@ -32,6 +32,7 @@ netsniff-ng-objs =	dissector.o \
 			proto_vlan_q_in_q.o \
 			proto_mpls_unicast.o \
 			proto_80211_mac_hdr.o \
+			irq.o \
 			xio.o \
 			xutils.o \
 			xmalloc.o \
diff --git a/trafgen.c b/trafgen.c
index bbce64c..d493614 100644
--- a/trafgen.c
+++ b/trafgen.c
@@ -37,6 +37,7 @@
 #include "mac80211.h"
 #include "xutils.h"
 #include "xio.h"
+#include "irq.h"
 #include "built_in.h"
 #include "trafgen_conf.h"
 #include "tprintf.h"
@@ -1083,6 +1084,7 @@ int main(int argc, char **argv)
 thread_out:
 	xunlockme();
 	destroy_shared_var(stats, ctx.cpus);
+	device_restore_irq_affinity_list();
 
 	free(ctx.device);
 	free(ctx.device_trans);
diff --git a/trafgen/Makefile b/trafgen/Makefile
index 8257ad1..914b61c 100644
--- a/trafgen/Makefile
+++ b/trafgen/Makefile
@@ -5,6 +5,7 @@ trafgen-libs =	$(shell pkg-config --libs libnl-3.0) \
 trafgen-objs =	xmalloc.o \
 		xio.o \
 		xutils.o \
+		irq.o \
 		mac80211.o \
 		ring_tx.o \
 		ring.o \
diff --git a/xutils.c b/xutils.c
index 5421d7d..a5fbb3c 100644
--- a/xutils.c
+++ b/xutils.c
@@ -608,114 +608,6 @@ void device_set_flags(const char *ifname, const short flags)
 	close(sock);
 }
 
-int device_irq_number(const char *ifname)
-{
-	/*
-	 * Since fetching IRQ numbers from SIOCGIFMAP is deprecated and not
-	 * supported anymore, we need to grab them from procfs
-	 */
-	int irq = 0;
-	char *buffp;
-	char buff[512];
-	char sysname[512];
-	FILE *fp;
-
-	if (!strncmp("lo", ifname, strlen("lo")))
-		return 0;
-
-	fp = fopen("/proc/interrupts", "r");
-	if (!fp)
-		panic("Cannot open /proc/interrupts!\n");
-
-	memset(buff, 0, sizeof(buff));
-	while (fgets(buff, sizeof(buff), fp) != NULL) {
-		buff[sizeof(buff) - 1] = 0;
-
-		if (strstr(buff, ifname) == NULL)
-			continue;
-
-		buffp = buff;
-		while (*buffp != ':')
-			buffp++;
-		*buffp = 0;
-		irq = atoi(buff);
-
-		memset(buff, 0, sizeof(buff));
-	}
-
-	fclose(fp);
-
-	if (irq != 0)
-		return irq;
-	/* 
-	 * Try sysfs as fallback. Probably wireless devices will be found
-	 * here. We return silently if it fails ...
-	 */
-	slprintf(sysname, sizeof(sysname), "/sys/class/net/%s/device/irq",
-		 ifname);
-
-	fp = fopen(sysname, "r");
-	if (!fp)
-		return -ENOENT;
-
-	memset(buff, 0, sizeof(buff));
-	if(fgets(buff, sizeof(buff), fp) != NULL) {
-		buff[sizeof(buff) - 1] = 0;
-		irq = atoi(buff);
-	}
-
-	fclose(fp);
-
-	return irq;
-}
-
-int device_set_irq_affinity_list(int irq, unsigned long from, unsigned long to)
-{
-	int ret, fd;
-	char file[256], list[64];
-
-	slprintf(file, sizeof(file), "/proc/irq/%d/smp_affinity_list", irq);
-	slprintf(list, sizeof(list), "%lu-%lu\n", from, to);
-
-	fd = open(file, O_WRONLY);
-	if (fd < 0)
-		return -ENOENT;
-
-	ret = write(fd, list, strlen(list));
-
-	close(fd);
-	return ret;
-}
-
-int device_bind_irq_to_cpu(int irq, int cpu)
-{
-	int ret;
-	char buff[256];
-	char file[256];
-	FILE *fp;
-
-	/* Note: first CPU begins with CPU 0 */
-	if (irq < 0 || cpu < 0)
-		return -EINVAL;
-
-	memset(file, 0, sizeof(file));
-	memset(buff, 0, sizeof(buff));
-
-	/* smp_affinity starts counting with CPU 1, 2, ... */
-	cpu = cpu + 1;
-	sprintf(file, "/proc/irq/%d/smp_affinity", irq);
-
-	fp = fopen(file, "w");
-	if (!fp)
-		return -ENOENT;
-
-	sprintf(buff, "%d", cpu);
-	ret = fwrite(buff, sizeof(buff), 1, fp);
-
-	fclose(fp);
-	return (ret > 0 ? 0 : ret);
-}
-
 void sock_print_net_stats(int sock)
 {
 	int ret;
diff --git a/xutils.h b/xutils.h
index 6e72b5c..28a307b 100644
--- a/xutils.h
+++ b/xutils.h
@@ -36,9 +36,6 @@ extern int ethtool_drvinf(const char *ifname, struct ethtool_drvinfo *drvinf);
 extern int ethtool_link(const char *ifname);
 extern int device_mtu(const char *ifname);
 extern int device_address(const char *ifname, int af, struct sockaddr_storage *ss);
-extern int device_irq_number(const char *ifname);
-extern int device_set_irq_affinity_list(int irq, unsigned long from, unsigned long to);
-extern int device_bind_irq_to_cpu(int irq, int cpu);
 extern void sock_print_net_stats(int sock);
 extern int device_ifindex(const char *ifname);
 extern short device_get_flags(const char *ifname);