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