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 }; 138