1 #ifndef _CCID_H
2 #define _CCID_H
3 /*
4  *  net/dccp/ccid.h
5  *
6  *  An implementation of the DCCP protocol
7  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
8  *
9  *  CCID infrastructure
10  *
11  *	This program is free software; you can redistribute it and/or modify it
12  *	under the terms of the GNU General Public License version 2 as
13  *	published by the Free Software Foundation.
14  */
15 
16 #include <net/sock.h>
17 #include <linux/compiler.h>
18 #include <linux/dccp.h>
19 #include <linux/list.h>
20 #include <linux/module.h>
21 
22 /* maximum value for a CCID (RFC 4340, 19.5) */
23 #define CCID_MAX		255
24 #define CCID_SLAB_NAME_LENGTH	32
25 
26 struct tcp_info;
27 
28 /**
29  *  struct ccid_operations  -  Interface to Congestion-Control Infrastructure
30  *
31  *  @ccid_id: numerical CCID ID (up to %CCID_MAX, cf. table 5 in RFC 4340, 10.)
32  *  @ccid_ccmps: the CCMPS including network/transport headers (0 when disabled)
33  *  @ccid_name: alphabetical identifier string for @ccid_id
34  *  @ccid_hc_{r,t}x_slab: memory pool for the receiver/sender half-connection
35  *  @ccid_hc_{r,t}x_obj_size: size of the receiver/sender half-connection socket
36  *
37  *  @ccid_hc_{r,t}x_init: CCID-specific initialisation routine (before startup)
38  *  @ccid_hc_{r,t}x_exit: CCID-specific cleanup routine (before destruction)
39  *  @ccid_hc_rx_packet_recv: implements the HC-receiver side
40  *  @ccid_hc_{r,t}x_parse_options: parsing routine for CCID/HC-specific options
41  *  @ccid_hc_{r,t}x_insert_options: insert routine for CCID/HC-specific options
42  *  @ccid_hc_tx_packet_recv: implements feedback processing for the HC-sender
43  *  @ccid_hc_tx_send_packet: implements the sending part of the HC-sender
44  *  @ccid_hc_tx_packet_sent: does accounting for packets in flight by HC-sender
45  *  @ccid_hc_{r,t}x_get_info: INET_DIAG information for HC-receiver/sender
46  *  @ccid_hc_{r,t}x_getsockopt: socket options specific to HC-receiver/sender
47  */
48 struct ccid_operations {
49 	unsigned char		ccid_id;
50 	__u32			ccid_ccmps;
51 	const char		*ccid_name;
52 	struct kmem_cache	*ccid_hc_rx_slab,
53 				*ccid_hc_tx_slab;
54 	char			ccid_hc_rx_slab_name[CCID_SLAB_NAME_LENGTH];
55 	char			ccid_hc_tx_slab_name[CCID_SLAB_NAME_LENGTH];
56 	__u32			ccid_hc_rx_obj_size,
57 				ccid_hc_tx_obj_size;
58 	/* Interface Routines */
59 	int		(*ccid_hc_rx_init)(struct ccid *ccid, struct sock *sk);
60 	int		(*ccid_hc_tx_init)(struct ccid *ccid, struct sock *sk);
61 	void		(*ccid_hc_rx_exit)(struct sock *sk);
62 	void		(*ccid_hc_tx_exit)(struct sock *sk);
63 	void		(*ccid_hc_rx_packet_recv)(struct sock *sk,
64 						  struct sk_buff *skb);
65 	int		(*ccid_hc_rx_parse_options)(struct sock *sk, u8 pkt,
66 						    u8 opt, u8 *val, u8 len);
67 	int		(*ccid_hc_rx_insert_options)(struct sock *sk,
68 						     struct sk_buff *skb);
69 	void		(*ccid_hc_tx_packet_recv)(struct sock *sk,
70 						  struct sk_buff *skb);
71 	int		(*ccid_hc_tx_parse_options)(struct sock *sk, u8 pkt,
72 						    u8 opt, u8 *val, u8 len);
73 	int		(*ccid_hc_tx_send_packet)(struct sock *sk,
74 						  struct sk_buff *skb);
75 	void		(*ccid_hc_tx_packet_sent)(struct sock *sk,
76 						  unsigned int len);
77 	void		(*ccid_hc_rx_get_info)(struct sock *sk,
78 					       struct tcp_info *info);
79 	void		(*ccid_hc_tx_get_info)(struct sock *sk,
80 					       struct tcp_info *info);
81 	int		(*ccid_hc_rx_getsockopt)(struct sock *sk,
82 						 const int optname, int len,
83 						 u32 __user *optval,
84 						 int __user *optlen);
85 	int		(*ccid_hc_tx_getsockopt)(struct sock *sk,
86 						 const int optname, int len,
87 						 u32 __user *optval,
88 						 int __user *optlen);
89 };
90 
91 extern struct ccid_operations ccid2_ops;
92 #ifdef CONFIG_IP_DCCP_CCID3
93 extern struct ccid_operations ccid3_ops;
94 #endif
95 
96 extern int  ccid_initialize_builtins(void);
97 extern void ccid_cleanup_builtins(void);
98 
99 struct ccid {
100 	struct ccid_operations *ccid_ops;
101 	char		       ccid_priv[0];
102 };
103 
ccid_priv(const struct ccid * ccid)104 static inline void *ccid_priv(const struct ccid *ccid)
105 {
106 	return (void *)ccid->ccid_priv;
107 }
108 
109 extern bool ccid_support_check(u8 const *ccid_array, u8 array_len);
110 extern int  ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len);
111 extern int  ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
112 					  char __user *, int __user *);
113 
114 extern struct ccid *ccid_new(const u8 id, struct sock *sk, bool rx);
115 
ccid_get_current_rx_ccid(struct dccp_sock * dp)116 static inline int ccid_get_current_rx_ccid(struct dccp_sock *dp)
117 {
118 	struct ccid *ccid = dp->dccps_hc_rx_ccid;
119 
120 	if (ccid == NULL || ccid->ccid_ops == NULL)
121 		return -1;
122 	return ccid->ccid_ops->ccid_id;
123 }
124 
ccid_get_current_tx_ccid(struct dccp_sock * dp)125 static inline int ccid_get_current_tx_ccid(struct dccp_sock *dp)
126 {
127 	struct ccid *ccid = dp->dccps_hc_tx_ccid;
128 
129 	if (ccid == NULL || ccid->ccid_ops == NULL)
130 		return -1;
131 	return ccid->ccid_ops->ccid_id;
132 }
133 
134 extern void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk);
135 extern void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk);
136 
137 /*
138  * Congestion control of queued data packets via CCID decision.
139  *
140  * The TX CCID performs its congestion-control by indicating whether and when a
141  * queued packet may be sent, using the return code of ccid_hc_tx_send_packet().
142  * The following modes are supported via the symbolic constants below:
143  * - timer-based pacing    (CCID returns a delay value in milliseconds);
144  * - autonomous dequeueing (CCID internally schedules dccps_xmitlet).
145  */
146 
147 enum ccid_dequeueing_decision {
148 	CCID_PACKET_SEND_AT_ONCE =	 0x00000,  /* "green light": no delay */
149 	CCID_PACKET_DELAY_MAX =		 0x0FFFF,  /* maximum delay in msecs  */
150 	CCID_PACKET_DELAY =		 0x10000,  /* CCID msec-delay mode */
151 	CCID_PACKET_WILL_DEQUEUE_LATER = 0x20000,  /* CCID autonomous mode */
152 	CCID_PACKET_ERR =		 0xF0000,  /* error condition */
153 };
154 
ccid_packet_dequeue_eval(const int return_code)155 static inline int ccid_packet_dequeue_eval(const int return_code)
156 {
157 	if (return_code < 0)
158 		return CCID_PACKET_ERR;
159 	if (return_code == 0)
160 		return CCID_PACKET_SEND_AT_ONCE;
161 	if (return_code <= CCID_PACKET_DELAY_MAX)
162 		return CCID_PACKET_DELAY;
163 	return return_code;
164 }
165 
ccid_hc_tx_send_packet(struct ccid * ccid,struct sock * sk,struct sk_buff * skb)166 static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk,
167 					 struct sk_buff *skb)
168 {
169 	if (ccid->ccid_ops->ccid_hc_tx_send_packet != NULL)
170 		return ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb);
171 	return CCID_PACKET_SEND_AT_ONCE;
172 }
173 
ccid_hc_tx_packet_sent(struct ccid * ccid,struct sock * sk,unsigned int len)174 static inline void ccid_hc_tx_packet_sent(struct ccid *ccid, struct sock *sk,
175 					  unsigned int len)
176 {
177 	if (ccid->ccid_ops->ccid_hc_tx_packet_sent != NULL)
178 		ccid->ccid_ops->ccid_hc_tx_packet_sent(sk, len);
179 }
180 
ccid_hc_rx_packet_recv(struct ccid * ccid,struct sock * sk,struct sk_buff * skb)181 static inline void ccid_hc_rx_packet_recv(struct ccid *ccid, struct sock *sk,
182 					  struct sk_buff *skb)
183 {
184 	if (ccid->ccid_ops->ccid_hc_rx_packet_recv != NULL)
185 		ccid->ccid_ops->ccid_hc_rx_packet_recv(sk, skb);
186 }
187 
ccid_hc_tx_packet_recv(struct ccid * ccid,struct sock * sk,struct sk_buff * skb)188 static inline void ccid_hc_tx_packet_recv(struct ccid *ccid, struct sock *sk,
189 					  struct sk_buff *skb)
190 {
191 	if (ccid->ccid_ops->ccid_hc_tx_packet_recv != NULL)
192 		ccid->ccid_ops->ccid_hc_tx_packet_recv(sk, skb);
193 }
194 
195 /**
196  * ccid_hc_tx_parse_options  -  Parse CCID-specific options sent by the receiver
197  * @pkt: type of packet that @opt appears on (RFC 4340, 5.1)
198  * @opt: the CCID-specific option type (RFC 4340, 5.8 and 10.3)
199  * @val: value of @opt
200  * @len: length of @val in bytes
201  */
ccid_hc_tx_parse_options(struct ccid * ccid,struct sock * sk,u8 pkt,u8 opt,u8 * val,u8 len)202 static inline int ccid_hc_tx_parse_options(struct ccid *ccid, struct sock *sk,
203 					   u8 pkt, u8 opt, u8 *val, u8 len)
204 {
205 	if (ccid->ccid_ops->ccid_hc_tx_parse_options == NULL)
206 		return 0;
207 	return ccid->ccid_ops->ccid_hc_tx_parse_options(sk, pkt, opt, val, len);
208 }
209 
210 /**
211  * ccid_hc_rx_parse_options  -  Parse CCID-specific options sent by the sender
212  * Arguments are analogous to ccid_hc_tx_parse_options()
213  */
ccid_hc_rx_parse_options(struct ccid * ccid,struct sock * sk,u8 pkt,u8 opt,u8 * val,u8 len)214 static inline int ccid_hc_rx_parse_options(struct ccid *ccid, struct sock *sk,
215 					   u8 pkt, u8 opt, u8 *val, u8 len)
216 {
217 	if (ccid->ccid_ops->ccid_hc_rx_parse_options == NULL)
218 		return 0;
219 	return ccid->ccid_ops->ccid_hc_rx_parse_options(sk, pkt, opt, val, len);
220 }
221 
ccid_hc_rx_insert_options(struct ccid * ccid,struct sock * sk,struct sk_buff * skb)222 static inline int ccid_hc_rx_insert_options(struct ccid *ccid, struct sock *sk,
223 					    struct sk_buff *skb)
224 {
225 	if (ccid->ccid_ops->ccid_hc_rx_insert_options != NULL)
226 		return ccid->ccid_ops->ccid_hc_rx_insert_options(sk, skb);
227 	return 0;
228 }
229 
ccid_hc_rx_get_info(struct ccid * ccid,struct sock * sk,struct tcp_info * info)230 static inline void ccid_hc_rx_get_info(struct ccid *ccid, struct sock *sk,
231 				       struct tcp_info *info)
232 {
233 	if (ccid->ccid_ops->ccid_hc_rx_get_info != NULL)
234 		ccid->ccid_ops->ccid_hc_rx_get_info(sk, info);
235 }
236 
ccid_hc_tx_get_info(struct ccid * ccid,struct sock * sk,struct tcp_info * info)237 static inline void ccid_hc_tx_get_info(struct ccid *ccid, struct sock *sk,
238 				       struct tcp_info *info)
239 {
240 	if (ccid->ccid_ops->ccid_hc_tx_get_info != NULL)
241 		ccid->ccid_ops->ccid_hc_tx_get_info(sk, info);
242 }
243 
ccid_hc_rx_getsockopt(struct ccid * ccid,struct sock * sk,const int optname,int len,u32 __user * optval,int __user * optlen)244 static inline int ccid_hc_rx_getsockopt(struct ccid *ccid, struct sock *sk,
245 					const int optname, int len,
246 					u32 __user *optval, int __user *optlen)
247 {
248 	int rc = -ENOPROTOOPT;
249 	if (ccid != NULL && ccid->ccid_ops->ccid_hc_rx_getsockopt != NULL)
250 		rc = ccid->ccid_ops->ccid_hc_rx_getsockopt(sk, optname, len,
251 						 optval, optlen);
252 	return rc;
253 }
254 
ccid_hc_tx_getsockopt(struct ccid * ccid,struct sock * sk,const int optname,int len,u32 __user * optval,int __user * optlen)255 static inline int ccid_hc_tx_getsockopt(struct ccid *ccid, struct sock *sk,
256 					const int optname, int len,
257 					u32 __user *optval, int __user *optlen)
258 {
259 	int rc = -ENOPROTOOPT;
260 	if (ccid != NULL && ccid->ccid_ops->ccid_hc_tx_getsockopt != NULL)
261 		rc = ccid->ccid_ops->ccid_hc_tx_getsockopt(sk, optname, len,
262 						 optval, optlen);
263 	return rc;
264 }
265 #endif /* _CCID_H */
266