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