arch/um/drivers/pcap_user.c

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