Root/
1 | /* |
2 | * llc_input.c - Minimal input path for LLC |
3 | * |
4 | * Copyright (c) 1997 by Procom Technology, Inc. |
5 | * 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br> |
6 | * |
7 | * This program can be redistributed or modified under the terms of the |
8 | * GNU General Public License as published by the Free Software Foundation. |
9 | * This program is distributed without any warranty or implied warranty |
10 | * of merchantability or fitness for a particular purpose. |
11 | * |
12 | * See the GNU General Public License for more details. |
13 | */ |
14 | #include <linux/netdevice.h> |
15 | #include <linux/slab.h> |
16 | #include <net/net_namespace.h> |
17 | #include <net/llc.h> |
18 | #include <net/llc_pdu.h> |
19 | #include <net/llc_sap.h> |
20 | |
21 | #if 0 |
22 | #define dprintk(args...) printk(KERN_DEBUG args) |
23 | #else |
24 | #define dprintk(args...) |
25 | #endif |
26 | |
27 | /* |
28 | * Packet handler for the station, registerable because in the minimal |
29 | * LLC core that is taking shape only the very minimal subset of LLC that |
30 | * is needed for things like IPX, Appletalk, etc will stay, with all the |
31 | * rest in the llc1 and llc2 modules. |
32 | */ |
33 | static void (*llc_station_handler)(struct sk_buff *skb); |
34 | |
35 | /* |
36 | * Packet handlers for LLC_DEST_SAP and LLC_DEST_CONN. |
37 | */ |
38 | static void (*llc_type_handlers[2])(struct llc_sap *sap, |
39 | struct sk_buff *skb); |
40 | |
41 | void llc_add_pack(int type, void (*handler)(struct llc_sap *sap, |
42 | struct sk_buff *skb)) |
43 | { |
44 | if (type == LLC_DEST_SAP || type == LLC_DEST_CONN) |
45 | llc_type_handlers[type - 1] = handler; |
46 | } |
47 | |
48 | void llc_remove_pack(int type) |
49 | { |
50 | if (type == LLC_DEST_SAP || type == LLC_DEST_CONN) |
51 | llc_type_handlers[type - 1] = NULL; |
52 | } |
53 | |
54 | void llc_set_station_handler(void (*handler)(struct sk_buff *skb)) |
55 | { |
56 | llc_station_handler = handler; |
57 | } |
58 | |
59 | /** |
60 | * llc_pdu_type - returns which LLC component must handle for PDU |
61 | * @skb: input skb |
62 | * |
63 | * This function returns which LLC component must handle this PDU. |
64 | */ |
65 | static __inline__ int llc_pdu_type(struct sk_buff *skb) |
66 | { |
67 | int type = LLC_DEST_CONN; /* I-PDU or S-PDU type */ |
68 | struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); |
69 | |
70 | if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) != LLC_PDU_TYPE_U) |
71 | goto out; |
72 | switch (LLC_U_PDU_CMD(pdu)) { |
73 | case LLC_1_PDU_CMD_XID: |
74 | case LLC_1_PDU_CMD_UI: |
75 | case LLC_1_PDU_CMD_TEST: |
76 | type = LLC_DEST_SAP; |
77 | break; |
78 | case LLC_2_PDU_CMD_SABME: |
79 | case LLC_2_PDU_CMD_DISC: |
80 | case LLC_2_PDU_RSP_UA: |
81 | case LLC_2_PDU_RSP_DM: |
82 | case LLC_2_PDU_RSP_FRMR: |
83 | break; |
84 | default: |
85 | type = LLC_DEST_INVALID; |
86 | break; |
87 | } |
88 | out: |
89 | return type; |
90 | } |
91 | |
92 | /** |
93 | * llc_fixup_skb - initializes skb pointers |
94 | * @skb: This argument points to incoming skb |
95 | * |
96 | * Initializes internal skb pointer to start of network layer by deriving |
97 | * length of LLC header; finds length of LLC control field in LLC header |
98 | * by looking at the two lowest-order bits of the first control field |
99 | * byte; field is either 3 or 4 bytes long. |
100 | */ |
101 | static inline int llc_fixup_skb(struct sk_buff *skb) |
102 | { |
103 | u8 llc_len = 2; |
104 | struct llc_pdu_un *pdu; |
105 | |
106 | if (unlikely(!pskb_may_pull(skb, sizeof(*pdu)))) |
107 | return 0; |
108 | |
109 | pdu = (struct llc_pdu_un *)skb->data; |
110 | if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) == LLC_PDU_TYPE_U) |
111 | llc_len = 1; |
112 | llc_len += 2; |
113 | |
114 | if (unlikely(!pskb_may_pull(skb, llc_len))) |
115 | return 0; |
116 | |
117 | skb->transport_header += llc_len; |
118 | skb_pull(skb, llc_len); |
119 | if (skb->protocol == htons(ETH_P_802_2)) { |
120 | __be16 pdulen = eth_hdr(skb)->h_proto; |
121 | s32 data_size = ntohs(pdulen) - llc_len; |
122 | |
123 | if (data_size < 0 || |
124 | ((skb_tail_pointer(skb) - |
125 | (u8 *)pdu) - llc_len) < data_size) |
126 | return 0; |
127 | if (unlikely(pskb_trim_rcsum(skb, data_size))) |
128 | return 0; |
129 | } |
130 | return 1; |
131 | } |
132 | |
133 | /** |
134 | * llc_rcv - 802.2 entry point from net lower layers |
135 | * @skb: received pdu |
136 | * @dev: device that receive pdu |
137 | * @pt: packet type |
138 | * |
139 | * When the system receives a 802.2 frame this function is called. It |
140 | * checks SAP and connection of received pdu and passes frame to |
141 | * llc_{station,sap,conn}_rcv for sending to proper state machine. If |
142 | * the frame is related to a busy connection (a connection is sending |
143 | * data now), it queues this frame in the connection's backlog. |
144 | */ |
145 | int llc_rcv(struct sk_buff *skb, struct net_device *dev, |
146 | struct packet_type *pt, struct net_device *orig_dev) |
147 | { |
148 | struct llc_sap *sap; |
149 | struct llc_pdu_sn *pdu; |
150 | int dest; |
151 | int (*rcv)(struct sk_buff *, struct net_device *, |
152 | struct packet_type *, struct net_device *); |
153 | |
154 | if (!net_eq(dev_net(dev), &init_net)) |
155 | goto drop; |
156 | |
157 | /* |
158 | * When the interface is in promisc. mode, drop all the crap that it |
159 | * receives, do not try to analyse it. |
160 | */ |
161 | if (unlikely(skb->pkt_type == PACKET_OTHERHOST)) { |
162 | dprintk("%s: PACKET_OTHERHOST\n", __func__); |
163 | goto drop; |
164 | } |
165 | skb = skb_share_check(skb, GFP_ATOMIC); |
166 | if (unlikely(!skb)) |
167 | goto out; |
168 | if (unlikely(!llc_fixup_skb(skb))) |
169 | goto drop; |
170 | pdu = llc_pdu_sn_hdr(skb); |
171 | if (unlikely(!pdu->dsap)) /* NULL DSAP, refer to station */ |
172 | goto handle_station; |
173 | sap = llc_sap_find(pdu->dsap); |
174 | if (unlikely(!sap)) {/* unknown SAP */ |
175 | dprintk("%s: llc_sap_find(%02X) failed!\n", __func__, |
176 | pdu->dsap); |
177 | goto drop; |
178 | } |
179 | /* |
180 | * First the upper layer protocols that don't need the full |
181 | * LLC functionality |
182 | */ |
183 | rcv = rcu_dereference(sap->rcv_func); |
184 | if (rcv) { |
185 | struct sk_buff *cskb = skb_clone(skb, GFP_ATOMIC); |
186 | if (cskb) |
187 | rcv(cskb, dev, pt, orig_dev); |
188 | } |
189 | dest = llc_pdu_type(skb); |
190 | if (unlikely(!dest || !llc_type_handlers[dest - 1])) |
191 | goto drop_put; |
192 | llc_type_handlers[dest - 1](sap, skb); |
193 | out_put: |
194 | llc_sap_put(sap); |
195 | out: |
196 | return 0; |
197 | drop: |
198 | kfree_skb(skb); |
199 | goto out; |
200 | drop_put: |
201 | kfree_skb(skb); |
202 | goto out_put; |
203 | handle_station: |
204 | if (!llc_station_handler) |
205 | goto drop; |
206 | llc_station_handler(skb); |
207 | goto out; |
208 | } |
209 | |
210 | EXPORT_SYMBOL(llc_add_pack); |
211 | EXPORT_SYMBOL(llc_remove_pack); |
212 | EXPORT_SYMBOL(llc_set_station_handler); |
213 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9