1 /* 1 /*
2 * llc_input.c - Minimal input path for LLC 2 * llc_input.c - Minimal input path for LLC
3 * 3 *
4 * Copyright (c) 1997 by Procom Technology, In 4 * Copyright (c) 1997 by Procom Technology, Inc.
5 * 2001-2003 by Arnaldo Carvalho 5 * 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6 * 6 *
7 * This program can be redistributed or modifi 7 * This program can be redistributed or modified under the terms of the
8 * GNU General Public License as published by 8 * GNU General Public License as published by the Free Software Foundation.
9 * This program is distributed without any war 9 * This program is distributed without any warranty or implied warranty
10 * of merchantability or fitness for a particu 10 * of merchantability or fitness for a particular purpose.
11 * 11 *
12 * See the GNU General Public License for more 12 * See the GNU General Public License for more details.
13 */ 13 */
14 #include <linux/netdevice.h> 14 #include <linux/netdevice.h>
15 #include <linux/slab.h> <<
16 #include <linux/export.h> <<
17 #include <net/net_namespace.h> 15 #include <net/net_namespace.h>
18 #include <net/llc.h> 16 #include <net/llc.h>
19 #include <net/llc_pdu.h> 17 #include <net/llc_pdu.h>
20 #include <net/llc_sap.h> 18 #include <net/llc_sap.h>
21 19
22 #if 0 20 #if 0
23 #define dprintk(args...) printk(KERN_DEBUG arg 21 #define dprintk(args...) printk(KERN_DEBUG args)
24 #else 22 #else
25 #define dprintk(args...) 23 #define dprintk(args...)
26 #endif 24 #endif
27 25
28 /* 26 /*
29 * Packet handler for the station, registerabl 27 * Packet handler for the station, registerable because in the minimal
30 * LLC core that is taking shape only the very 28 * LLC core that is taking shape only the very minimal subset of LLC that
31 * is needed for things like IPX, Appletalk, e 29 * is needed for things like IPX, Appletalk, etc will stay, with all the
32 * rest in the llc1 and llc2 modules. 30 * rest in the llc1 and llc2 modules.
33 */ 31 */
34 static void (*llc_station_handler)(struct sk_b 32 static void (*llc_station_handler)(struct sk_buff *skb);
35 33
36 /* 34 /*
37 * Packet handlers for LLC_DEST_SAP and LLC_DE 35 * Packet handlers for LLC_DEST_SAP and LLC_DEST_CONN.
38 */ 36 */
39 static void (*llc_type_handlers[2])(struct llc 37 static void (*llc_type_handlers[2])(struct llc_sap *sap,
40 struct sk_ 38 struct sk_buff *skb);
41 39
42 void llc_add_pack(int type, void (*handler)(st 40 void llc_add_pack(int type, void (*handler)(struct llc_sap *sap,
43 st 41 struct sk_buff *skb))
44 { 42 {
45 smp_wmb(); /* ensure initialisation is <<
46 if (type == LLC_DEST_SAP || type == LL 43 if (type == LLC_DEST_SAP || type == LLC_DEST_CONN)
47 llc_type_handlers[type - 1] = 44 llc_type_handlers[type - 1] = handler;
48 } 45 }
49 46
50 void llc_remove_pack(int type) 47 void llc_remove_pack(int type)
51 { 48 {
52 if (type == LLC_DEST_SAP || type == LL 49 if (type == LLC_DEST_SAP || type == LLC_DEST_CONN)
53 llc_type_handlers[type - 1] = 50 llc_type_handlers[type - 1] = NULL;
54 synchronize_net(); <<
55 } 51 }
56 52
57 void llc_set_station_handler(void (*handler)(s 53 void llc_set_station_handler(void (*handler)(struct sk_buff *skb))
58 { 54 {
59 /* Ensure initialisation is complete b <<
60 if (handler) <<
61 smp_wmb(); <<
62 <<
63 llc_station_handler = handler; 55 llc_station_handler = handler;
64 <<
65 if (!handler) <<
66 synchronize_net(); <<
67 } 56 }
68 57
69 /** 58 /**
70 * llc_pdu_type - returns which LLC compo 59 * llc_pdu_type - returns which LLC component must handle for PDU
71 * @skb: input skb 60 * @skb: input skb
72 * 61 *
73 * This function returns which LLC compon 62 * This function returns which LLC component must handle this PDU.
74 */ 63 */
75 static __inline__ int llc_pdu_type(struct sk_b 64 static __inline__ int llc_pdu_type(struct sk_buff *skb)
76 { 65 {
77 int type = LLC_DEST_CONN; /* I-PDU or 66 int type = LLC_DEST_CONN; /* I-PDU or S-PDU type */
78 struct llc_pdu_sn *pdu = llc_pdu_sn_hd 67 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
79 68
80 if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) 69 if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) != LLC_PDU_TYPE_U)
81 goto out; 70 goto out;
82 switch (LLC_U_PDU_CMD(pdu)) { 71 switch (LLC_U_PDU_CMD(pdu)) {
83 case LLC_1_PDU_CMD_XID: 72 case LLC_1_PDU_CMD_XID:
84 case LLC_1_PDU_CMD_UI: 73 case LLC_1_PDU_CMD_UI:
85 case LLC_1_PDU_CMD_TEST: 74 case LLC_1_PDU_CMD_TEST:
86 type = LLC_DEST_SAP; 75 type = LLC_DEST_SAP;
87 break; 76 break;
88 case LLC_2_PDU_CMD_SABME: 77 case LLC_2_PDU_CMD_SABME:
89 case LLC_2_PDU_CMD_DISC: 78 case LLC_2_PDU_CMD_DISC:
90 case LLC_2_PDU_RSP_UA: 79 case LLC_2_PDU_RSP_UA:
91 case LLC_2_PDU_RSP_DM: 80 case LLC_2_PDU_RSP_DM:
92 case LLC_2_PDU_RSP_FRMR: 81 case LLC_2_PDU_RSP_FRMR:
93 break; 82 break;
94 default: 83 default:
95 type = LLC_DEST_INVALID; 84 type = LLC_DEST_INVALID;
96 break; 85 break;
97 } 86 }
98 out: 87 out:
99 return type; 88 return type;
100 } 89 }
101 90
102 /** 91 /**
103 * llc_fixup_skb - initializes skb pointe 92 * llc_fixup_skb - initializes skb pointers
104 * @skb: This argument points to incoming 93 * @skb: This argument points to incoming skb
105 * 94 *
106 * Initializes internal skb pointer to st 95 * Initializes internal skb pointer to start of network layer by deriving
107 * length of LLC header; finds length of 96 * length of LLC header; finds length of LLC control field in LLC header
108 * by looking at the two lowest-order bit 97 * by looking at the two lowest-order bits of the first control field
109 * byte; field is either 3 or 4 bytes lon 98 * byte; field is either 3 or 4 bytes long.
110 */ 99 */
111 static inline int llc_fixup_skb(struct sk_buff 100 static inline int llc_fixup_skb(struct sk_buff *skb)
112 { 101 {
113 u8 llc_len = 2; 102 u8 llc_len = 2;
114 struct llc_pdu_un *pdu; 103 struct llc_pdu_un *pdu;
115 104
116 if (unlikely(!pskb_may_pull(skb, sizeo 105 if (unlikely(!pskb_may_pull(skb, sizeof(*pdu))))
117 return 0; 106 return 0;
118 107
119 pdu = (struct llc_pdu_un *)skb->data; 108 pdu = (struct llc_pdu_un *)skb->data;
120 if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) 109 if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) == LLC_PDU_TYPE_U)
121 llc_len = 1; 110 llc_len = 1;
122 llc_len += 2; 111 llc_len += 2;
123 112
124 if (unlikely(!pskb_may_pull(skb, llc_l 113 if (unlikely(!pskb_may_pull(skb, llc_len)))
125 return 0; 114 return 0;
126 115
127 skb->transport_header += llc_len; 116 skb->transport_header += llc_len;
128 skb_pull(skb, llc_len); 117 skb_pull(skb, llc_len);
129 if (skb->protocol == htons(ETH_P_802_2 118 if (skb->protocol == htons(ETH_P_802_2)) {
130 __be16 pdulen; !! 119 __be16 pdulen = eth_hdr(skb)->h_proto;
131 s32 data_size; !! 120 s32 data_size = ntohs(pdulen) - llc_len;
132 <<
133 if (skb->mac_len < ETH_HLEN) <<
134 return 0; <<
135 <<
136 pdulen = eth_hdr(skb)->h_proto <<
137 data_size = ntohs(pdulen) - ll <<
138 121
139 if (data_size < 0 || 122 if (data_size < 0 ||
140 !pskb_may_pull(skb, data_s !! 123 ((skb_tail_pointer(skb) -
>> 124 (u8 *)pdu) - llc_len) < data_size)
141 return 0; 125 return 0;
142 if (unlikely(pskb_trim_rcsum(s 126 if (unlikely(pskb_trim_rcsum(skb, data_size)))
143 return 0; 127 return 0;
144 } 128 }
145 return 1; 129 return 1;
146 } 130 }
147 131
148 /** 132 /**
149 * llc_rcv - 802.2 entry point from net l 133 * llc_rcv - 802.2 entry point from net lower layers
150 * @skb: received pdu 134 * @skb: received pdu
151 * @dev: device that receive pdu 135 * @dev: device that receive pdu
152 * @pt: packet type 136 * @pt: packet type
153 * @orig_dev: the original receive net de <<
154 * 137 *
155 * When the system receives a 802.2 frame 138 * When the system receives a 802.2 frame this function is called. It
156 * checks SAP and connection of received 139 * checks SAP and connection of received pdu and passes frame to
157 * llc_{station,sap,conn}_rcv for sending 140 * llc_{station,sap,conn}_rcv for sending to proper state machine. If
158 * the frame is related to a busy connect 141 * the frame is related to a busy connection (a connection is sending
159 * data now), it queues this frame in the 142 * data now), it queues this frame in the connection's backlog.
160 */ 143 */
161 int llc_rcv(struct sk_buff *skb, struct net_de 144 int llc_rcv(struct sk_buff *skb, struct net_device *dev,
162 struct packet_type *pt, struct net 145 struct packet_type *pt, struct net_device *orig_dev)
163 { 146 {
164 struct llc_sap *sap; 147 struct llc_sap *sap;
165 struct llc_pdu_sn *pdu; 148 struct llc_pdu_sn *pdu;
166 int dest; 149 int dest;
167 int (*rcv)(struct sk_buff *, struct ne 150 int (*rcv)(struct sk_buff *, struct net_device *,
168 struct packet_type *, struc 151 struct packet_type *, struct net_device *);
169 void (*sta_handler)(struct sk_buff *sk !! 152
170 void (*sap_handler)(struct llc_sap *sa !! 153 if (!net_eq(dev_net(dev), &init_net))
>> 154 goto drop;
171 155
172 /* 156 /*
173 * When the interface is in promisc. m 157 * When the interface is in promisc. mode, drop all the crap that it
174 * receives, do not try to analyse it. 158 * receives, do not try to analyse it.
175 */ 159 */
176 if (unlikely(skb->pkt_type == PACKET_O 160 if (unlikely(skb->pkt_type == PACKET_OTHERHOST)) {
177 dprintk("%s: PACKET_OTHERHOST\ 161 dprintk("%s: PACKET_OTHERHOST\n", __func__);
178 goto drop; 162 goto drop;
179 } 163 }
180 skb = skb_share_check(skb, GFP_ATOMIC) 164 skb = skb_share_check(skb, GFP_ATOMIC);
181 if (unlikely(!skb)) 165 if (unlikely(!skb))
182 goto out; 166 goto out;
183 if (unlikely(!llc_fixup_skb(skb))) 167 if (unlikely(!llc_fixup_skb(skb)))
184 goto drop; 168 goto drop;
185 pdu = llc_pdu_sn_hdr(skb); 169 pdu = llc_pdu_sn_hdr(skb);
186 if (unlikely(!pdu->dsap)) /* NULL DSAP 170 if (unlikely(!pdu->dsap)) /* NULL DSAP, refer to station */
187 goto handle_station; 171 goto handle_station;
188 sap = llc_sap_find(pdu->dsap); 172 sap = llc_sap_find(pdu->dsap);
189 if (unlikely(!sap)) {/* unknown SAP */ 173 if (unlikely(!sap)) {/* unknown SAP */
190 dprintk("%s: llc_sap_find(%02X 174 dprintk("%s: llc_sap_find(%02X) failed!\n", __func__,
191 pdu->dsap); 175 pdu->dsap);
192 goto drop; 176 goto drop;
193 } 177 }
194 /* 178 /*
195 * First the upper layer protocols tha 179 * First the upper layer protocols that don't need the full
196 * LLC functionality 180 * LLC functionality
197 */ 181 */
198 rcv = rcu_dereference(sap->rcv_func); 182 rcv = rcu_dereference(sap->rcv_func);
199 dest = llc_pdu_type(skb); !! 183 if (rcv) {
200 sap_handler = dest ? READ_ONCE(llc_typ !! 184 struct sk_buff *cskb = skb_clone(skb, GFP_ATOMIC);
201 if (unlikely(!sap_handler)) { !! 185 if (cskb)
202 if (rcv) !! 186 rcv(cskb, dev, pt, orig_dev);
203 rcv(skb, dev, pt, orig <<
204 else <<
205 kfree_skb(skb); <<
206 } else { <<
207 if (rcv) { <<
208 struct sk_buff *cskb = <<
209 if (cskb) <<
210 rcv(cskb, dev, <<
211 } <<
212 sap_handler(sap, skb); <<
213 } 187 }
>> 188 dest = llc_pdu_type(skb);
>> 189 if (unlikely(!dest || !llc_type_handlers[dest - 1]))
>> 190 goto drop_put;
>> 191 llc_type_handlers[dest - 1](sap, skb);
>> 192 out_put:
214 llc_sap_put(sap); 193 llc_sap_put(sap);
215 out: 194 out:
216 return 0; 195 return 0;
217 drop: 196 drop:
218 kfree_skb(skb); 197 kfree_skb(skb);
219 goto out; 198 goto out;
>> 199 drop_put:
>> 200 kfree_skb(skb);
>> 201 goto out_put;
220 handle_station: 202 handle_station:
221 sta_handler = READ_ONCE(llc_station_ha !! 203 if (!llc_station_handler)
222 if (!sta_handler) <<
223 goto drop; 204 goto drop;
224 sta_handler(skb); !! 205 llc_station_handler(skb);
225 goto out; 206 goto out;
226 } 207 }
227 208
228 EXPORT_SYMBOL(llc_add_pack); 209 EXPORT_SYMBOL(llc_add_pack);
229 EXPORT_SYMBOL(llc_remove_pack); 210 EXPORT_SYMBOL(llc_remove_pack);
230 EXPORT_SYMBOL(llc_set_station_handler); 211 EXPORT_SYMBOL(llc_set_station_handler);
231 212
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