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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 | /* * SNAP data link layer. Derived from 802.2 * * Alan Cox <Alan.Cox@linux.org>, from the 802.2 layer by Greg Page. * Merged in additions from Greg Page's psnap.c. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/module.h> #include <linux/netdevice.h> #include <linux/skbuff.h> #include <net/datalink.h> #include <net/p8022.h> #include <net/psnap.h> #include <linux/mm.h> #include <linux/in.h> #include <linux/init.h> static struct datalink_proto *snap_list = NULL; static struct datalink_proto *snap_dl = NULL; /* 802.2 DL for SNAP */ /* * Find a snap client by matching the 5 bytes. */ static struct datalink_proto *find_snap_client(unsigned char *desc) { struct datalink_proto *proto; for (proto = snap_list; proto != NULL && memcmp(proto->type, desc, 5) ; proto = proto->next); return proto; } /* * A SNAP packet has arrived */ int snap_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt) { static struct packet_type psnap_packet_type = { 0, NULL, /* All Devices */ snap_rcv, NULL, NULL, }; struct datalink_proto *proto; proto = find_snap_client(skb->h.raw); if (proto != NULL) { /* * Pass the frame on. */ skb->h.raw += 5; skb->nh.raw += 5; skb_pull(skb,5); if (psnap_packet_type.type == 0) psnap_packet_type.type=htons(ETH_P_SNAP); return proto->rcvfunc(skb, dev, &psnap_packet_type); } skb->sk = NULL; kfree_skb(skb); return 0; } /* * Put a SNAP header on a frame and pass to 802.2 */ static void snap_datalink_header(struct datalink_proto *dl, struct sk_buff *skb, unsigned char *dest_node) { memcpy(skb_push(skb,5),dl->type,5); snap_dl->datalink_header(snap_dl, skb, dest_node); } /* * Set up the SNAP layer */ EXPORT_SYMBOL(register_snap_client); EXPORT_SYMBOL(unregister_snap_client); static int __init snap_init(void) { snap_dl=register_8022_client(0xAA, snap_rcv); if(snap_dl==NULL) printk("SNAP - unable to register with 802.2\n"); return 0; } module_init(snap_init); /* * Register SNAP clients. We don't yet use this for IP. */ struct datalink_proto *register_snap_client(unsigned char *desc, int (*rcvfunc)(struct sk_buff *, struct net_device *, struct packet_type *)) { struct datalink_proto *proto; if (find_snap_client(desc) != NULL) return NULL; proto = (struct datalink_proto *) kmalloc(sizeof(*proto), GFP_ATOMIC); if (proto != NULL) { memcpy(proto->type, desc,5); proto->type_len = 5; proto->rcvfunc = rcvfunc; proto->header_length = 5+snap_dl->header_length; proto->datalink_header = snap_datalink_header; proto->string_name = "SNAP"; proto->next = snap_list; snap_list = proto; } return proto; } /* * Unregister SNAP clients. Protocols no longer want to play with us ... */ void unregister_snap_client(unsigned char *desc) { struct datalink_proto **clients = &snap_list; struct datalink_proto *tmp; unsigned long flags; save_flags(flags); cli(); while ((tmp = *clients) != NULL) { if (memcmp(tmp->type,desc,5) == 0) { *clients = tmp->next; kfree(tmp); break; } else clients = &tmp->next; } restore_flags(flags); } |