irq.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2009 - 2013 Daniel Borkmann.
   4  * Copyright 2009, 2010 Emmanuel Roullit.
   5  * Subject to the GPL, version 2.
   6  */
   7
   8 #include <stdio.h>
   9 #include <string.h>
  10 #include <stdlib.h>
  11 #include <errno.h>
  12 #include <sys/types.h>
  13 #include <sys/stat.h>
  14 #include <fcntl.h>
  15
  16 #include "irq.h"
  17 #include "str.h"
  18 #include "die.h"
  19 #include "xutils.h"
  20
  21 int device_irq_number(const char *ifname)
  22 {
  23         int irq = 0;
  24         char buff[128], sysname[128];
  25         FILE *fp;
  26
  27         if (!strncmp("lo", ifname, strlen("lo")))
  28                 return 0;
  29
  30         slprintf(sysname, sizeof(sysname),
  31                  "/sys/class/net/%s/device/irq",
  32                  ifname);
  33
  34         fp = fopen(sysname, "r");
  35         if (!fp)
  36                 return -ENOENT;
  37
  38         memset(buff, 0, sizeof(buff));
  39
  40         if (fgets(buff, sizeof(buff), fp) != NULL) {
  41                 buff[sizeof(buff) - 1] = 0;
  42                 irq = atoi(buff);
  43         }
  44
  45         fclose(fp);
  46         return irq;
  47 }
  48
  49 static char nic_irq_affinity_list[128];
  50 static bool nic_irq_stored = false;
  51 static int  nic_irq = -1;
  52
  53 static void device_save_irq_affinity_list(void)
  54 {
  55         int ret, fd;
  56         char file[128];
  57
  58         bug_on(nic_irq_stored);
  59
  60         slprintf(file, sizeof(file),
  61                  "/proc/irq/%d/smp_affinity_list", nic_irq);
  62
  63         fd = open(file, O_RDONLY);
  64         if (fd < 0)
  65                 return;
  66
  67         memset(nic_irq_affinity_list, 0, sizeof(nic_irq_affinity_list));
  68
  69         ret = read(fd, nic_irq_affinity_list,
  70                    sizeof(nic_irq_affinity_list));
  71         if (ret < 0)
  72                 panic("Cannot store NIC IRQ affinity!\n");
  73
  74         close(fd);
  75
  76         nic_irq_stored = true;
  77 }
  78
  79 void device_restore_irq_affinity_list(void)
  80 {
  81         int ret, fd;
  82         char file[128];
  83
  84         if (!nic_irq_stored)
  85                 return;
  86
  87         bug_on(nic_irq == -1);
  88
  89         slprintf(file, sizeof(file),
  90                  "/proc/irq/%d/smp_affinity_list", nic_irq);
  91
  92         fd = open(file, O_WRONLY);
  93         if (fd < 0)
  94                 return;
  95
  96         ret = write(fd, nic_irq_affinity_list,
  97                     sizeof(nic_irq_affinity_list));
  98         if (ret < 0)
  99                 panic("Cannot restore NIC IRQ affinity!\n");
 100
 101         close(fd);
 102 }
 103
 104 int device_set_irq_affinity_list(int irq, unsigned long from, unsigned long to)
 105 {
 106         int ret, fd;
 107         char file[128], list[64];
 108
 109         if (!nic_irq_stored) {
 110                 nic_irq = irq;
 111                 device_save_irq_affinity_list();
 112         }
 113
 114         slprintf(file, sizeof(file), "/proc/irq/%d/smp_affinity_list", irq);
 115         slprintf(list, sizeof(list), "%lu-%lu\n", from, to);
 116
 117         fd = open(file, O_WRONLY);
 118         if (fd < 0)
 119                 return -ENOENT;
 120
 121         ret = write(fd, list, strlen(list));
 122
 123         close(fd);
 124         return ret;
 125 }
 126
 127 int device_bind_irq_to_cpu(int irq, int cpu)
 128 {
 129         return device_set_irq_affinity_list(irq, cpu, cpu);
 130 }