arch/um/drivers/pcap_user.c

   1 /*
   2  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL.
   4  */
   5
   6 #include <errno.h>
   7 #include <pcap.h>
   8 #include <string.h>
   9 #include <asm/types.h>
  10 #include "net_user.h"
  11 #include "pcap_user.h"
  12 #include "kern_constants.h"
  13 #include "um_malloc.h"
  14 #include "user.h"
  15
  16 #define MAX_PACKET (ETH_MAX_PACKET + ETH_HEADER_OTHER)
  17
  18 #define PCAP_FD(p) (*(int *)(p))
  19
  20 static int pcap_user_init(void *data, void *dev)
  21 {
  22         struct pcap_data *pri = data;
  23         pcap_t *p;
  24         char errors[PCAP_ERRBUF_SIZE];
  25
  26         p = pcap_open_live(pri->host_if, MAX_PACKET, pri->promisc, 0, errors);
  27         if (p == NULL) {
  28                 printk(UM_KERN_ERR "pcap_user_init : pcap_open_live failed - "
  29                        "'%s'\n", errors);
  30                 return -EINVAL;
  31         }
  32
  33         pri->dev = dev;
  34         pri->pcap = p;
  35         return 0;
  36 }
  37
  38 static int pcap_open(void *data)
  39 {
  40         struct pcap_data *pri = data;
  41         __u32 netmask;
  42         int err;
  43
  44         if (pri->pcap == NULL)
  45                 return -ENODEV;
  46
  47         if (pri->filter != NULL) {
  48                 err = dev_netmask(pri->dev, &netmask);
  49                 if (err < 0) {
  50                         printk(UM_KERN_ERR "pcap_open : dev_netmask failed\n");
  51                         return -EIO;
  52                 }
  53
  54                 pri->compiled = kmalloc(sizeof(struct bpf_program),
  55                                         UM_GFP_KERNEL);
  56                 if (pri->compiled == NULL) {
  57                         printk(UM_KERN_ERR "pcap_open : kmalloc failed\n");
  58                         return -ENOMEM;
  59                 }
  60
  61                 err = pcap_compile(pri->pcap,
  62                                    (struct bpf_program *) pri->compiled,
  63                                    pri->filter, pri->optimize, netmask);
  64                 if (err < 0) {
  65                         printk(UM_KERN_ERR "pcap_open : pcap_compile failed - "
  66                                "'%s'\n", pcap_geterr(pri->pcap));
  67                         goto out;
  68                 }
  69
  70                 err = pcap_setfilter(pri->pcap, pri->compiled);
  71                 if (err < 0) {
  72                         printk(UM_KERN_ERR "pcap_open : pcap_setfilter "
  73                                "failed - '%s'\n", pcap_geterr(pri->pcap));
  74                         goto out;
  75                 }
  76         }
  77
  78         return PCAP_FD(pri->pcap);
  79
  80  out:
  81         kfree(pri->compiled);
  82         return -EIO;
  83 }
  84
  85 static void pcap_remove(void *data)
  86 {
  87         struct pcap_data *pri = data;
  88
  89         if (pri->compiled != NULL)
  90                 pcap_freecode(pri->compiled);
  91
  92         if (pri->pcap != NULL)
  93                 pcap_close(pri->pcap);
  94 }
  95
  96 struct pcap_handler_data {
  97         char *buffer;
  98         int len;
  99 };
 100
 101 static void handler(u_char *data, const struct pcap_pkthdr *header,
 102                     const u_char *packet)
 103 {
 104         int len;
 105
 106         struct pcap_handler_data *hdata = (struct pcap_handler_data *) data;
 107
 108         len = hdata->len < header->caplen ? hdata->len : header->caplen;
 109         memcpy(hdata->buffer, packet, len);
 110         hdata->len = len;
 111 }
 112
 113 int pcap_user_read(int fd, void *buffer, int len, struct pcap_data *pri)
 114 {
 115         struct pcap_handler_data hdata = ((struct pcap_handler_data)
 116                                           { .buffer     = buffer,
 117                                             .len        = len });
 118         int n;
 119
 120         n = pcap_dispatch(pri->pcap, 1, handler, (u_char *) &hdata);
 121         if (n < 0) {
 122                 printk(UM_KERN_ERR "pcap_dispatch failed - %s\n",
 123                        pcap_geterr(pri->pcap));
 124                 return -EIO;
 125         }
 126         else if (n == 0)
 127                 return 0;
 128         return hdata.len;
 129 }
 130
 131 const struct net_user_info pcap_user_info = {
 132         .init           = pcap_user_init,
 133         .open           = pcap_open,
 134         .close          = NULL,
 135         .remove         = pcap_remove,
 136         .set_mtu        = NULL,
 137         .add_address    = NULL,
 138         .delete_address = NULL,
 139         .max_packet     = MAX_PACKET - ETH_HEADER_OTHER
 140 };