linux/arch/um/drivers/pcap_user.c
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   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 "um_malloc.h"
  13
  14#define PCAP_FD(p) (*(int *)(p))
  15
  16static int pcap_user_init(void *data, void *dev)
  17{
  18        struct pcap_data *pri = data;
  19        pcap_t *p;
  20        char errors[PCAP_ERRBUF_SIZE];
  21
  22        p = pcap_open_live(pri->host_if, ETH_MAX_PACKET + ETH_HEADER_OTHER,
  23                           pri->promisc, 0, errors);
  24        if (p == NULL) {
  25                printk(UM_KERN_ERR "pcap_user_init : pcap_open_live failed - "
  26                       "'%s'\n", errors);
  27                return -EINVAL;
  28        }
  29
  30        pri->dev = dev;
  31        pri->pcap = p;
  32        return 0;
  33}
  34
  35static int pcap_open(void *data)
  36{
  37        struct pcap_data *pri = data;
  38        __u32 netmask;
  39        int err;
  40
  41        if (pri->pcap == NULL)
  42                return -ENODEV;
  43
  44        if (pri->filter != NULL) {
  45                err = dev_netmask(pri->dev, &netmask);
  46                if (err < 0) {
  47                        printk(UM_KERN_ERR "pcap_open : dev_netmask failed\n");
  48                        return -EIO;
  49                }
  50
  51                pri->compiled = uml_kmalloc(sizeof(struct bpf_program),
  52                                        UM_GFP_KERNEL);
  53                if (pri->compiled == NULL) {
  54                        printk(UM_KERN_ERR "pcap_open : kmalloc failed\n");
  55                        return -ENOMEM;
  56                }
  57
  58                err = pcap_compile(pri->pcap,
  59                                   (struct bpf_program *) pri->compiled,
  60                                   pri->filter, pri->optimize, netmask);
  61                if (err < 0) {
  62                        printk(UM_KERN_ERR "pcap_open : pcap_compile failed - "
  63                               "'%s'\n", pcap_geterr(pri->pcap));
  64                        goto out;
  65                }
  66
  67                err = pcap_setfilter(pri->pcap, pri->compiled);
  68                if (err < 0) {
  69                        printk(UM_KERN_ERR "pcap_open : pcap_setfilter "
  70                               "failed - '%s'\n", pcap_geterr(pri->pcap));
  71                        goto out;
  72                }
  73        }
  74
  75        return PCAP_FD(pri->pcap);
  76
  77 out:
  78        kfree(pri->compiled);
  79        return -EIO;
  80}
  81
  82static 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
  93struct pcap_handler_data {
  94        char *buffer;
  95        int len;
  96};
  97
  98static 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
 110int 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
 128const struct net_user_info pcap_user_info = {
 129        .init           = pcap_user_init,
 130        .open           = pcap_open,
 131        .close          = NULL,
 132        .remove         = pcap_remove,
 133        .add_address    = NULL,
 134        .delete_address = NULL,
 135        .mtu            = ETH_MAX_PACKET,
 136        .max_packet     = ETH_MAX_PACKET + ETH_HEADER_OTHER,
 137};
 138
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