1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  net/dccp/ccid.c
4  *
5  *  An implementation of the DCCP protocol
6  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
7  *
8  *  CCID infrastructure
9  */
10 
11 #include <linux/slab.h>
12 
13 #include "ccid.h"
14 #include "ccids/lib/tfrc.h"
15 
16 static struct ccid_operations *ccids[] = {
17 	&ccid2_ops,
18 #ifdef CONFIG_IP_DCCP_CCID3
19 	&ccid3_ops,
20 #endif
21 };
22 
ccid_by_number(const u8 id)23 static struct ccid_operations *ccid_by_number(const u8 id)
24 {
25 	int i;
26 
27 	for (i = 0; i < ARRAY_SIZE(ccids); i++)
28 		if (ccids[i]->ccid_id == id)
29 			return ccids[i];
30 	return NULL;
31 }
32 
33 /* check that up to @array_len members in @ccid_array are supported */
ccid_support_check(u8 const * ccid_array,u8 array_len)34 bool ccid_support_check(u8 const *ccid_array, u8 array_len)
35 {
36 	while (array_len > 0)
37 		if (ccid_by_number(ccid_array[--array_len]) == NULL)
38 			return false;
39 	return true;
40 }
41 
42 /**
43  * ccid_get_builtin_ccids  -  Populate a list of built-in CCIDs
44  * @ccid_array: pointer to copy into
45  * @array_len: value to return length into
46  *
47  * This function allocates memory - caller must see that it is freed after use.
48  */
ccid_get_builtin_ccids(u8 ** ccid_array,u8 * array_len)49 int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len)
50 {
51 	*ccid_array = kmalloc(ARRAY_SIZE(ccids), gfp_any());
52 	if (*ccid_array == NULL)
53 		return -ENOBUFS;
54 
55 	for (*array_len = 0; *array_len < ARRAY_SIZE(ccids); *array_len += 1)
56 		(*ccid_array)[*array_len] = ccids[*array_len]->ccid_id;
57 	return 0;
58 }
59 
ccid_getsockopt_builtin_ccids(struct sock * sk,int len,char __user * optval,int __user * optlen)60 int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
61 				  char __user *optval, int __user *optlen)
62 {
63 	u8 *ccid_array, array_len;
64 	int err = 0;
65 
66 	if (ccid_get_builtin_ccids(&ccid_array, &array_len))
67 		return -ENOBUFS;
68 
69 	if (put_user(array_len, optlen))
70 		err = -EFAULT;
71 	else if (len > 0 && copy_to_user(optval, ccid_array,
72 					 len > array_len ? array_len : len))
73 		err = -EFAULT;
74 
75 	kfree(ccid_array);
76 	return err;
77 }
78 
ccid_kmem_cache_create(int obj_size,char * slab_name_fmt,const char * fmt,...)79 static __printf(3, 4) struct kmem_cache *ccid_kmem_cache_create(int obj_size, char *slab_name_fmt, const char *fmt,...)
80 {
81 	struct kmem_cache *slab;
82 	va_list args;
83 
84 	va_start(args, fmt);
85 	vsnprintf(slab_name_fmt, CCID_SLAB_NAME_LENGTH, fmt, args);
86 	va_end(args);
87 
88 	slab = kmem_cache_create(slab_name_fmt, sizeof(struct ccid) + obj_size, 0,
89 				 SLAB_HWCACHE_ALIGN, NULL);
90 	return slab;
91 }
92 
ccid_kmem_cache_destroy(struct kmem_cache * slab)93 static void ccid_kmem_cache_destroy(struct kmem_cache *slab)
94 {
95 	kmem_cache_destroy(slab);
96 }
97 
ccid_activate(struct ccid_operations * ccid_ops)98 static int __init ccid_activate(struct ccid_operations *ccid_ops)
99 {
100 	int err = -ENOBUFS;
101 
102 	ccid_ops->ccid_hc_rx_slab =
103 			ccid_kmem_cache_create(ccid_ops->ccid_hc_rx_obj_size,
104 					       ccid_ops->ccid_hc_rx_slab_name,
105 					       "ccid%u_hc_rx_sock",
106 					       ccid_ops->ccid_id);
107 	if (ccid_ops->ccid_hc_rx_slab == NULL)
108 		goto out;
109 
110 	ccid_ops->ccid_hc_tx_slab =
111 			ccid_kmem_cache_create(ccid_ops->ccid_hc_tx_obj_size,
112 					       ccid_ops->ccid_hc_tx_slab_name,
113 					       "ccid%u_hc_tx_sock",
114 					       ccid_ops->ccid_id);
115 	if (ccid_ops->ccid_hc_tx_slab == NULL)
116 		goto out_free_rx_slab;
117 
118 	pr_info("DCCP: Activated CCID %d (%s)\n",
119 		ccid_ops->ccid_id, ccid_ops->ccid_name);
120 	err = 0;
121 out:
122 	return err;
123 out_free_rx_slab:
124 	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
125 	ccid_ops->ccid_hc_rx_slab = NULL;
126 	goto out;
127 }
128 
ccid_deactivate(struct ccid_operations * ccid_ops)129 static void ccid_deactivate(struct ccid_operations *ccid_ops)
130 {
131 	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
132 	ccid_ops->ccid_hc_tx_slab = NULL;
133 	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
134 	ccid_ops->ccid_hc_rx_slab = NULL;
135 
136 	pr_info("DCCP: Deactivated CCID %d (%s)\n",
137 		ccid_ops->ccid_id, ccid_ops->ccid_name);
138 }
139 
ccid_new(const u8 id,struct sock * sk,bool rx)140 struct ccid *ccid_new(const u8 id, struct sock *sk, bool rx)
141 {
142 	struct ccid_operations *ccid_ops = ccid_by_number(id);
143 	struct ccid *ccid = NULL;
144 
145 	if (ccid_ops == NULL)
146 		goto out;
147 
148 	ccid = kmem_cache_alloc(rx ? ccid_ops->ccid_hc_rx_slab :
149 				     ccid_ops->ccid_hc_tx_slab, gfp_any());
150 	if (ccid == NULL)
151 		goto out;
152 	ccid->ccid_ops = ccid_ops;
153 	if (rx) {
154 		memset(ccid + 1, 0, ccid_ops->ccid_hc_rx_obj_size);
155 		if (ccid->ccid_ops->ccid_hc_rx_init != NULL &&
156 		    ccid->ccid_ops->ccid_hc_rx_init(ccid, sk) != 0)
157 			goto out_free_ccid;
158 	} else {
159 		memset(ccid + 1, 0, ccid_ops->ccid_hc_tx_obj_size);
160 		if (ccid->ccid_ops->ccid_hc_tx_init != NULL &&
161 		    ccid->ccid_ops->ccid_hc_tx_init(ccid, sk) != 0)
162 			goto out_free_ccid;
163 	}
164 out:
165 	return ccid;
166 out_free_ccid:
167 	kmem_cache_free(rx ? ccid_ops->ccid_hc_rx_slab :
168 			ccid_ops->ccid_hc_tx_slab, ccid);
169 	ccid = NULL;
170 	goto out;
171 }
172 
ccid_hc_rx_delete(struct ccid * ccid,struct sock * sk)173 void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk)
174 {
175 	if (ccid != NULL) {
176 		if (ccid->ccid_ops->ccid_hc_rx_exit != NULL)
177 			ccid->ccid_ops->ccid_hc_rx_exit(sk);
178 		kmem_cache_free(ccid->ccid_ops->ccid_hc_rx_slab, ccid);
179 	}
180 }
181 
ccid_hc_tx_delete(struct ccid * ccid,struct sock * sk)182 void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk)
183 {
184 	if (ccid != NULL) {
185 		if (ccid->ccid_ops->ccid_hc_tx_exit != NULL)
186 			ccid->ccid_ops->ccid_hc_tx_exit(sk);
187 		kmem_cache_free(ccid->ccid_ops->ccid_hc_tx_slab, ccid);
188 	}
189 }
190 
ccid_initialize_builtins(void)191 int __init ccid_initialize_builtins(void)
192 {
193 	int i, err = tfrc_lib_init();
194 
195 	if (err)
196 		return err;
197 
198 	for (i = 0; i < ARRAY_SIZE(ccids); i++) {
199 		err = ccid_activate(ccids[i]);
200 		if (err)
201 			goto unwind_registrations;
202 	}
203 	return 0;
204 
205 unwind_registrations:
206 	while(--i >= 0)
207 		ccid_deactivate(ccids[i]);
208 	tfrc_lib_exit();
209 	return err;
210 }
211 
ccid_cleanup_builtins(void)212 void ccid_cleanup_builtins(void)
213 {
214 	int i;
215 
216 	for (i = 0; i < ARRAY_SIZE(ccids); i++)
217 		ccid_deactivate(ccids[i]);
218 	tfrc_lib_exit();
219 }
220