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