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
16static struct ccid_operations *ccids[] = {
17	&ccid2_ops,
18#ifdef CONFIG_IP_DCCP_CCID3
19	&ccid3_ops,
20#endif
21};
22
23static 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 */
34bool 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 */
49int 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
60int 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
79static __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
93static void ccid_kmem_cache_destroy(struct kmem_cache *slab)
94{
95	kmem_cache_destroy(slab);
96}
97
98static 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;
121out:
122	return err;
123out_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
129static 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
140struct 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	}
164out:
165	return ccid;
166out_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
173void 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
182void 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
191int __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
205unwind_registrations:
206	while(--i >= 0)
207		ccid_deactivate(ccids[i]);
208	tfrc_lib_exit();
209	return err;
210}
211
212void 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