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> <<
18 #include <net/llc.h> 15 #include <net/llc.h>
19 #include <net/llc_pdu.h> 16 #include <net/llc_pdu.h>
20 #include <net/llc_sap.h> 17 #include <net/llc_sap.h>
21 18
22 #if 0 19 #if 0
23 #define dprintk(args...) printk(KERN_DEBUG arg 20 #define dprintk(args...) printk(KERN_DEBUG args)
24 #else 21 #else
25 #define dprintk(args...) 22 #define dprintk(args...)
26 #endif 23 #endif
27 24
28 /* 25 /*
29 * Packet handler for the station, registerabl 26 * Packet handler for the station, registerable because in the minimal
30 * LLC core that is taking shape only the very 27 * LLC core that is taking shape only the very minimal subset of LLC that
31 * is needed for things like IPX, Appletalk, e 28 * is needed for things like IPX, Appletalk, etc will stay, with all the
32 * rest in the llc1 and llc2 modules. 29 * rest in the llc1 and llc2 modules.
33 */ 30 */
34 static void (*llc_station_handler)(struct sk_b 31 static void (*llc_station_handler)(struct sk_buff *skb);
35 32
36 /* 33 /*
37 * Packet handlers for LLC_DEST_SAP and LLC_DE 34 * Packet handlers for LLC_DEST_SAP and LLC_DEST_CONN.
38 */ 35 */
39 static void (*llc_type_handlers[2])(struct llc 36 static void (*llc_type_handlers[2])(struct llc_sap *sap,
40 struct sk_ 37 struct sk_buff *skb);
41 38
42 void llc_add_pack(int type, void (*handler)(st 39 void llc_add_pack(int type, void (*handler)(struct llc_sap *sap,
43 st 40 struct sk_buff *skb))
44 { 41 {
45 smp_wmb(); /* ensure initialisation is <<
46 if (type == LLC_DEST_SAP || type == LL 42 if (type == LLC_DEST_SAP || type == LLC_DEST_CONN)
47 llc_type_handlers[type - 1] = 43 llc_type_handlers[type - 1] = handler;
48 } 44 }
49 45
50 void llc_remove_pack(int type) 46 void llc_remove_pack(int type)
51 { 47 {
52 if (type == LLC_DEST_SAP || type == LL 48 if (type == LLC_DEST_SAP || type == LLC_DEST_CONN)
53 llc_type_handlers[type - 1] = 49 llc_type_handlers[type - 1] = NULL;
54 synchronize_net(); <<
55 } 50 }
56 51
57 void llc_set_station_handler(void (*handler)(s 52 void llc_set_station_handler(void (*handler)(struct sk_buff *skb))
58 { 53 {
59 /* Ensure initialisation is complete b <<
60 if (handler) <<
61 smp_wmb(); <<
62 <<
63 llc_station_handler = handler; 54 llc_station_handler = handler;
64 <<
65 if (!handler) <<
66 synchronize_net(); <<
67 } 55 }
68 56
69 /** 57 /**
70 * llc_pdu_type - returns which LLC compo 58 * llc_pdu_type - returns which LLC component must handle for PDU
71 * @skb: input skb 59 * @skb: input skb
72 * 60 *
73 * This function returns which LLC compon 61 * This function returns which LLC component must handle this PDU.
74 */ 62 */
75 static __inline__ int llc_pdu_type(struct sk_b 63 static __inline__ int llc_pdu_type(struct sk_buff *skb)
76 { 64 {
77 int type = LLC_DEST_CONN; /* I-PDU or 65 int type = LLC_DEST_CONN; /* I-PDU or S-PDU type */
78 struct llc_pdu_sn *pdu = llc_pdu_sn_hd 66 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
79 67
80 if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) 68 if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) != LLC_PDU_TYPE_U)
81 goto out; 69 goto out;
82 switch (LLC_U_PDU_CMD(pdu)) { 70 switch (LLC_U_PDU_CMD(pdu)) {
83 case LLC_1_PDU_CMD_XID: 71 case LLC_1_PDU_CMD_XID:
84 case LLC_1_PDU_CMD_UI: 72 case LLC_1_PDU_CMD_UI:
85 case LLC_1_PDU_CMD_TEST: 73 case LLC_1_PDU_CMD_TEST:
86 type = LLC_DEST_SAP; 74 type = LLC_DEST_SAP;
87 break; 75 break;
88 case LLC_2_PDU_CMD_SABME: 76 case LLC_2_PDU_CMD_SABME:
89 case LLC_2_PDU_CMD_DISC: 77 case LLC_2_PDU_CMD_DISC:
90 case LLC_2_PDU_RSP_UA: 78 case LLC_2_PDU_RSP_UA:
91 case LLC_2_PDU_RSP_DM: 79 case LLC_2_PDU_RSP_DM:
92 case LLC_2_PDU_RSP_FRMR: 80 case LLC_2_PDU_RSP_FRMR:
93 break; 81 break;
94 default: 82 default:
95 type = LLC_DEST_INVALID; 83 type = LLC_DEST_INVALID;
96 break; 84 break;
97 } 85 }
98 out: 86 out:
99 return type; 87 return type;
100 } 88 }
101 89
102 /** 90 /**
103 * llc_fixup_skb - initializes skb pointe 91 * llc_fixup_skb - initializes skb pointers
104 * @skb: This argument points to incoming 92 * @skb: This argument points to incoming skb
105 * 93 *
106 * Initializes internal skb pointer to st 94 * Initializes internal skb pointer to start of network layer by deriving
107 * length of LLC header; finds length of 95 * length of LLC header; finds length of LLC control field in LLC header
108 * by looking at the two lowest-order bit 96 * by looking at the two lowest-order bits of the first control field
109 * byte; field is either 3 or 4 bytes lon 97 * byte; field is either 3 or 4 bytes long.
110 */ 98 */
111 static inline int llc_fixup_skb(struct sk_buff 99 static inline int llc_fixup_skb(struct sk_buff *skb)
112 { 100 {
113 u8 llc_len = 2; 101 u8 llc_len = 2;
114 struct llc_pdu_un *pdu; !! 102 struct llc_pdu_sn *pdu;
115 103
116 if (unlikely(!pskb_may_pull(skb, sizeo !! 104 if (!pskb_may_pull(skb, sizeof(*pdu)))
117 return 0; 105 return 0;
118 106
119 pdu = (struct llc_pdu_un *)skb->data; !! 107 pdu = (struct llc_pdu_sn *)skb->data;
120 if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) 108 if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) == LLC_PDU_TYPE_U)
121 llc_len = 1; 109 llc_len = 1;
122 llc_len += 2; 110 llc_len += 2;
123 !! 111 skb->h.raw += llc_len;
124 if (unlikely(!pskb_may_pull(skb, llc_l <<
125 return 0; <<
126 <<
127 skb->transport_header += llc_len; <<
128 skb_pull(skb, llc_len); 112 skb_pull(skb, llc_len);
129 if (skb->protocol == htons(ETH_P_802_2 113 if (skb->protocol == htons(ETH_P_802_2)) {
130 __be16 pdulen; !! 114 u16 pdulen = ((struct ethhdr *)skb->mac.raw)->h_proto,
131 s32 data_size; !! 115 data_size = ntohs(pdulen) - llc_len;
132 116
133 if (skb->mac_len < ETH_HLEN) !! 117 skb_trim(skb, data_size);
134 return 0; <<
135 <<
136 pdulen = eth_hdr(skb)->h_proto <<
137 data_size = ntohs(pdulen) - ll <<
138 <<
139 if (data_size < 0 || <<
140 !pskb_may_pull(skb, data_s <<
141 return 0; <<
142 if (unlikely(pskb_trim_rcsum(s <<
143 return 0; <<
144 } 118 }
145 return 1; 119 return 1;
146 } 120 }
147 121
148 /** 122 /**
149 * llc_rcv - 802.2 entry point from net l 123 * llc_rcv - 802.2 entry point from net lower layers
150 * @skb: received pdu 124 * @skb: received pdu
151 * @dev: device that receive pdu 125 * @dev: device that receive pdu
152 * @pt: packet type 126 * @pt: packet type
153 * @orig_dev: the original receive net de <<
154 * 127 *
155 * When the system receives a 802.2 frame 128 * When the system receives a 802.2 frame this function is called. It
156 * checks SAP and connection of received 129 * checks SAP and connection of received pdu and passes frame to
157 * llc_{station,sap,conn}_rcv for sending 130 * llc_{station,sap,conn}_rcv for sending to proper state machine. If
158 * the frame is related to a busy connect 131 * the frame is related to a busy connection (a connection is sending
159 * data now), it queues this frame in the 132 * data now), it queues this frame in the connection's backlog.
160 */ 133 */
161 int llc_rcv(struct sk_buff *skb, struct net_de 134 int llc_rcv(struct sk_buff *skb, struct net_device *dev,
162 struct packet_type *pt, struct net !! 135 struct packet_type *pt)
163 { 136 {
164 struct llc_sap *sap; 137 struct llc_sap *sap;
165 struct llc_pdu_sn *pdu; 138 struct llc_pdu_sn *pdu;
166 int dest; 139 int dest;
167 int (*rcv)(struct sk_buff *, struct ne <<
168 struct packet_type *, struc <<
169 void (*sta_handler)(struct sk_buff *sk <<
170 void (*sap_handler)(struct llc_sap *sa <<
171 140
172 /* 141 /*
173 * When the interface is in promisc. m 142 * When the interface is in promisc. mode, drop all the crap that it
174 * receives, do not try to analyse it. 143 * receives, do not try to analyse it.
175 */ 144 */
176 if (unlikely(skb->pkt_type == PACKET_O 145 if (unlikely(skb->pkt_type == PACKET_OTHERHOST)) {
177 dprintk("%s: PACKET_OTHERHOST\ !! 146 dprintk("%s: PACKET_OTHERHOST\n", __FUNCTION__);
178 goto drop; 147 goto drop;
179 } 148 }
180 skb = skb_share_check(skb, GFP_ATOMIC) 149 skb = skb_share_check(skb, GFP_ATOMIC);
181 if (unlikely(!skb)) 150 if (unlikely(!skb))
182 goto out; 151 goto out;
183 if (unlikely(!llc_fixup_skb(skb))) 152 if (unlikely(!llc_fixup_skb(skb)))
184 goto drop; 153 goto drop;
185 pdu = llc_pdu_sn_hdr(skb); 154 pdu = llc_pdu_sn_hdr(skb);
186 if (unlikely(!pdu->dsap)) /* NULL DSAP 155 if (unlikely(!pdu->dsap)) /* NULL DSAP, refer to station */
187 goto handle_station; 156 goto handle_station;
188 sap = llc_sap_find(pdu->dsap); 157 sap = llc_sap_find(pdu->dsap);
189 if (unlikely(!sap)) {/* unknown SAP */ 158 if (unlikely(!sap)) {/* unknown SAP */
190 dprintk("%s: llc_sap_find(%02X !! 159 dprintk("%s: llc_sap_find(%02X) failed!\n", __FUNCTION__,
191 pdu->dsap); !! 160 pdu->dsap);
192 goto drop; 161 goto drop;
193 } 162 }
194 /* 163 /*
195 * First the upper layer protocols tha 164 * First the upper layer protocols that don't need the full
196 * LLC functionality 165 * LLC functionality
197 */ 166 */
198 rcv = rcu_dereference(sap->rcv_func); !! 167 if (sap->rcv_func) {
199 dest = llc_pdu_type(skb); !! 168 sap->rcv_func(skb, dev, pt);
200 sap_handler = dest ? READ_ONCE(llc_typ !! 169 goto out;
201 if (unlikely(!sap_handler)) { <<
202 if (rcv) <<
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 } 170 }
214 llc_sap_put(sap); !! 171 dest = llc_pdu_type(skb);
>> 172 if (unlikely(!dest || !llc_type_handlers[dest - 1]))
>> 173 goto drop;
>> 174 llc_type_handlers[dest - 1](sap, skb);
215 out: 175 out:
216 return 0; 176 return 0;
217 drop: 177 drop:
218 kfree_skb(skb); 178 kfree_skb(skb);
219 goto out; 179 goto out;
220 handle_station: 180 handle_station:
221 sta_handler = READ_ONCE(llc_station_ha !! 181 if (!llc_station_handler)
222 if (!sta_handler) <<
223 goto drop; 182 goto drop;
224 sta_handler(skb); !! 183 llc_station_handler(skb);
225 goto out; 184 goto out;
226 } 185 }
227 186
228 EXPORT_SYMBOL(llc_add_pack); 187 EXPORT_SYMBOL(llc_add_pack);
229 EXPORT_SYMBOL(llc_remove_pack); 188 EXPORT_SYMBOL(llc_remove_pack);
230 EXPORT_SYMBOL(llc_set_station_handler); 189 EXPORT_SYMBOL(llc_set_station_handler);
231 190
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