1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 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 16 static 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 35 static 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 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 .add_address = NULL, 134 .delete_address = NULL, 135 .mtu = ETH_MAX_PACKET, 136 .max_packet = ETH_MAX_PACKET + ETH_HEADER_OTHER, 137 }; 138