/*
 * xfrm algorithm interface
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/pfkeyv2.h>
#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include <net/xfrm.h>
#if defined(CONFIG_INET_AH) || defined(CONFIG_INET_AH_MODULE) || defined(CONFIG_INET6_AH) || defined(CONFIG_INET6_AH_MODULE)
#include <net/ah.h>
#endif
#if defined(CONFIG_INET_ESP) || defined(CONFIG_INET_ESP_MODULE) || defined(CONFIG_INET6_ESP) || defined(CONFIG_INET6_ESP_MODULE)
#include <net/esp.h>
#endif

/*
 * Algorithms supported by IPsec.  These entries contain properties which
 * are used in key negotiation and xfrm processing, and are used to verify
 * that instantiated crypto transforms have correct parameters for IPsec
 * purposes.
 */
static struct xfrm_algo_desc aead_list[] = {
{
        .name = "rfc4106(gcm(aes))",

        .uinfo = {
                .aead = {
                        .icv_truncbits = 64,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_AES_GCM_ICV8,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 256
        }
},
{
        .name = "rfc4106(gcm(aes))",

        .uinfo = {
                .aead = {
                        .icv_truncbits = 96,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_AES_GCM_ICV12,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 256
        }
},
{
        .name = "rfc4106(gcm(aes))",

        .uinfo = {
                .aead = {
                        .icv_truncbits = 128,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_AES_GCM_ICV16,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 256
        }
},
{
        .name = "rfc4309(ccm(aes))",

        .uinfo = {
                .aead = {
                        .icv_truncbits = 64,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_AES_CCM_ICV8,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 256
        }
},
{
        .name = "rfc4309(ccm(aes))",

        .uinfo = {
                .aead = {
                        .icv_truncbits = 96,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_AES_CCM_ICV12,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 256
        }
},
{
        .name = "rfc4309(ccm(aes))",

        .uinfo = {
                .aead = {
                        .icv_truncbits = 128,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_AES_CCM_ICV16,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 256
        }
},
};

static struct xfrm_algo_desc aalg_list[] = {
{
        .name = "digest_null",

        .uinfo = {
                .auth = {
                        .icv_truncbits = 0,
                        .icv_fullbits = 0,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_AALG_NULL,
                .sadb_alg_ivlen = 0,
                .sadb_alg_minbits = 0,
                .sadb_alg_maxbits = 0
        }
},
{
        .name = "hmac(md5)",
        .compat = "md5",

        .uinfo = {
                .auth = {
                        .icv_truncbits = 96,
                        .icv_fullbits = 128,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_AALG_MD5HMAC,
                .sadb_alg_ivlen = 0,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 128
        }
},
{
        .name = "hmac(sha1)",
        .compat = "sha1",

        .uinfo = {
                .auth = {
                        .icv_truncbits = 96,
                        .icv_fullbits = 160,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_AALG_SHA1HMAC,
                .sadb_alg_ivlen = 0,
                .sadb_alg_minbits = 160,
                .sadb_alg_maxbits = 160
        }
},
{
        .name = "hmac(sha256)",
        .compat = "sha256",

        .uinfo = {
                .auth = {
                        .icv_truncbits = 96,
                        .icv_fullbits = 256,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_AALG_SHA2_256HMAC,
                .sadb_alg_ivlen = 0,
                .sadb_alg_minbits = 256,
                .sadb_alg_maxbits = 256
        }
},
{
        .name = "hmac(rmd160)",
        .compat = "rmd160",

        .uinfo = {
                .auth = {
                        .icv_truncbits = 96,
                        .icv_fullbits = 160,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_AALG_RIPEMD160HMAC,
                .sadb_alg_ivlen = 0,
                .sadb_alg_minbits = 160,
                .sadb_alg_maxbits = 160
        }
},
{
        .name = "xcbc(aes)",

        .uinfo = {
                .auth = {
                        .icv_truncbits = 96,
                        .icv_fullbits = 128,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_AALG_AES_XCBC_MAC,
                .sadb_alg_ivlen = 0,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 128
        }
},
};

static struct xfrm_algo_desc ealg_list[] = {
{
        .name = "ecb(cipher_null)",
        .compat = "cipher_null",

        .uinfo = {
                .encr = {
                        .blockbits = 8,
                        .defkeybits = 0,
                }
        },

        .desc = {
                .sadb_alg_id =  SADB_EALG_NULL,
                .sadb_alg_ivlen = 0,
                .sadb_alg_minbits = 0,
                .sadb_alg_maxbits = 0
        }
},
{
        .name = "cbc(des)",
        .compat = "des",

        .uinfo = {
                .encr = {
                        .blockbits = 64,
                        .defkeybits = 64,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_EALG_DESCBC,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 64,
                .sadb_alg_maxbits = 64
        }
},
{
        .name = "cbc(des3_ede)",
        .compat = "des3_ede",

        .uinfo = {
                .encr = {
                        .blockbits = 64,
                        .defkeybits = 192,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_EALG_3DESCBC,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 192,
                .sadb_alg_maxbits = 192
        }
},
{
        .name = "cbc(cast5)",
        .compat = "cast5",

        .uinfo = {
                .encr = {
                        .blockbits = 64,
                        .defkeybits = 128,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_CASTCBC,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 40,
                .sadb_alg_maxbits = 128
        }
},
{
        .name = "cbc(blowfish)",
        .compat = "blowfish",

        .uinfo = {
                .encr = {
                        .blockbits = 64,
                        .defkeybits = 128,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_BLOWFISHCBC,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 40,
                .sadb_alg_maxbits = 448
        }
},
{
        .name = "cbc(aes)",
        .compat = "aes",

        .uinfo = {
                .encr = {
                        .blockbits = 128,
                        .defkeybits = 128,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_AESCBC,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 256
        }
},
{
        .name = "cbc(serpent)",
        .compat = "serpent",

        .uinfo = {
                .encr = {
                        .blockbits = 128,
                        .defkeybits = 128,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_SERPENTCBC,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 256,
        }
},
{
        .name = "cbc(camellia)",

        .uinfo = {
                .encr = {
                        .blockbits = 128,
                        .defkeybits = 128,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_CAMELLIACBC,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 256
        }
},
{
        .name = "cbc(twofish)",
        .compat = "twofish",

        .uinfo = {
                .encr = {
                        .blockbits = 128,
                        .defkeybits = 128,
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_TWOFISHCBC,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 256
        }
},
{
        .name = "rfc3686(ctr(aes))",

        .uinfo = {
                .encr = {
                        .blockbits = 128,
                        .defkeybits = 160, /* 128-bit key + 32-bit nonce */
                }
        },

        .desc = {
                .sadb_alg_id = SADB_X_EALG_AESCTR,
                .sadb_alg_ivlen = 8,
                .sadb_alg_minbits = 128,
                .sadb_alg_maxbits = 256
        }
},
};

static struct xfrm_algo_desc calg_list[] = {
{
        .name = "deflate",
        .uinfo = {
                .comp = {
                        .threshold = 90,
                }
        },
        .desc = { .sadb_alg_id = SADB_X_CALG_DEFLATE }
},
{
        .name = "lzs",
        .uinfo = {
                .comp = {
                        .threshold = 90,
                }
        },
        .desc = { .sadb_alg_id = SADB_X_CALG_LZS }
},
{
        .name = "lzjh",
        .uinfo = {
                .comp = {
                        .threshold = 50,
                }
        },
        .desc = { .sadb_alg_id = SADB_X_CALG_LZJH }
},
};

static inline int aead_entries(void)
{
        return ARRAY_SIZE(aead_list);
}

static inline int aalg_entries(void)
{
        return ARRAY_SIZE(aalg_list);
}

static inline int ealg_entries(void)
{
        return ARRAY_SIZE(ealg_list);
}

static inline int calg_entries(void)
{
        return ARRAY_SIZE(calg_list);
}

struct xfrm_algo_list {
        struct xfrm_algo_desc *algs;
        int entries;
        u32 type;
        u32 mask;
};

static const struct xfrm_algo_list xfrm_aead_list = {
        .algs = aead_list,
        .entries = ARRAY_SIZE(aead_list),
        .type = CRYPTO_ALG_TYPE_AEAD,
        .mask = CRYPTO_ALG_TYPE_MASK,
};

static const struct xfrm_algo_list xfrm_aalg_list = {
        .algs = aalg_list,
        .entries = ARRAY_SIZE(aalg_list),
        .type = CRYPTO_ALG_TYPE_HASH,
        .mask = CRYPTO_ALG_TYPE_HASH_MASK,
};

static const struct xfrm_algo_list xfrm_ealg_list = {
        .algs = ealg_list,
        .entries = ARRAY_SIZE(ealg_list),
        .type = CRYPTO_ALG_TYPE_BLKCIPHER,
        .mask = CRYPTO_ALG_TYPE_BLKCIPHER_MASK,
};

static const struct xfrm_algo_list xfrm_calg_list = {
        .algs = calg_list,
        .entries = ARRAY_SIZE(calg_list),
        .type = CRYPTO_ALG_TYPE_COMPRESS,
        .mask = CRYPTO_ALG_TYPE_MASK,
};

static struct xfrm_algo_desc *xfrm_find_algo(
        const struct xfrm_algo_list *algo_list,
        int match(const struct xfrm_algo_desc *entry, const void *data),
        const void *data, int probe)
{
        struct xfrm_algo_desc *list = algo_list->algs;
        int i, status;

        for (i = 0; i < algo_list->entries; i++) {
                if (!match(list + i, data))
                        continue;

                if (list[i].available)
                        return &list[i];

                if (!probe)
                        break;

                status = crypto_has_alg(list[i].name, algo_list->type,
                                        algo_list->mask);
                if (!status)
                        break;

                list[i].available = status;
                return &list[i];
        }
        return NULL;
}

static int xfrm_alg_id_match(const struct xfrm_algo_desc *entry,
                             const void *data)
{
        return entry->desc.sadb_alg_id == (unsigned long)data;
}

struct xfrm_algo_desc *xfrm_aalg_get_byid(int alg_id)
{
        return xfrm_find_algo(&xfrm_aalg_list, xfrm_alg_id_match,
                              (void *)(unsigned long)alg_id, 1);
}
EXPORT_SYMBOL_GPL(xfrm_aalg_get_byid);

struct xfrm_algo_desc *xfrm_ealg_get_byid(int alg_id)
{
        return xfrm_find_algo(&xfrm_ealg_list, xfrm_alg_id_match,
                              (void *)(unsigned long)alg_id, 1);
}
EXPORT_SYMBOL_GPL(xfrm_ealg_get_byid);

struct xfrm_algo_desc *xfrm_calg_get_byid(int alg_id)
{
        return xfrm_find_algo(&xfrm_calg_list, xfrm_alg_id_match,
                              (void *)(unsigned long)alg_id, 1);
}
EXPORT_SYMBOL_GPL(xfrm_calg_get_byid);

static int xfrm_alg_name_match(const struct xfrm_algo_desc *entry,
                               const void *data)
{
        const char *name = data;

        return name && (!strcmp(name, entry->name) ||
                        (entry->compat && !strcmp(name, entry->compat)));
}

struct xfrm_algo_desc *xfrm_aalg_get_byname(char *name, int probe)
{
        return xfrm_find_algo(&xfrm_aalg_list, xfrm_alg_name_match, name,
                              probe);
}
EXPORT_SYMBOL_GPL(xfrm_aalg_get_byname);

struct xfrm_algo_desc *xfrm_ealg_get_byname(char *name, int probe)
{
        return xfrm_find_algo(&xfrm_ealg_list, xfrm_alg_name_match, name,
                              probe);
}
EXPORT_SYMBOL_GPL(xfrm_ealg_get_byname);

struct xfrm_algo_desc *xfrm_calg_get_byname(char *name, int probe)
{
        return xfrm_find_algo(&xfrm_calg_list, xfrm_alg_name_match, name,
                              probe);
}
EXPORT_SYMBOL_GPL(xfrm_calg_get_byname);

struct xfrm_aead_name {
        const char *name;
        int icvbits;
};

static int xfrm_aead_name_match(const struct xfrm_algo_desc *entry,
                                const void *data)
{
        const struct xfrm_aead_name *aead = data;
        const char *name = aead->name;

        return aead->icvbits == entry->uinfo.aead.icv_truncbits && name &&
               !strcmp(name, entry->name);
}

struct xfrm_algo_desc *xfrm_aead_get_byname(char *name, int icv_len, int probe)
{
        struct xfrm_aead_name data = {
                .name = name,
                .icvbits = icv_len,
        };

        return xfrm_find_algo(&xfrm_aead_list, xfrm_aead_name_match, &data,
                              probe);
}
EXPORT_SYMBOL_GPL(xfrm_aead_get_byname);

struct xfrm_algo_desc *xfrm_aalg_get_byidx(unsigned int idx)
{
        if (idx >= aalg_entries())
                return NULL;

        return &aalg_list[idx];
}
EXPORT_SYMBOL_GPL(xfrm_aalg_get_byidx);

struct xfrm_algo_desc *xfrm_ealg_get_byidx(unsigned int idx)
{
        if (idx >= ealg_entries())
                return NULL;

        return &ealg_list[idx];
}
EXPORT_SYMBOL_GPL(xfrm_ealg_get_byidx);

/*
 * Probe for the availability of crypto algorithms, and set the available
 * flag for any algorithms found on the system.  This is typically called by
 * pfkey during userspace SA add, update or register.
 */
void xfrm_probe_algs(void)
{
        int i, status;

        BUG_ON(in_softirq());

        for (i = 0; i < aalg_entries(); i++) {
                status = crypto_has_hash(aalg_list[i].name, 0,
                                         CRYPTO_ALG_ASYNC);
                if (aalg_list[i].available != status)
                        aalg_list[i].available = status;
        }

        for (i = 0; i < ealg_entries(); i++) {
                status = crypto_has_blkcipher(ealg_list[i].name, 0,
                                              CRYPTO_ALG_ASYNC);
                if (ealg_list[i].available != status)
                        ealg_list[i].available = status;
        }

        for (i = 0; i < calg_entries(); i++) {
                status = crypto_has_comp(calg_list[i].name, 0,
                                         CRYPTO_ALG_ASYNC);
                if (calg_list[i].available != status)
                        calg_list[i].available = status;
        }
}
EXPORT_SYMBOL_GPL(xfrm_probe_algs);

int xfrm_count_auth_supported(void)
{
        int i, n;

        for (i = 0, n = 0; i < aalg_entries(); i++)
                if (aalg_list[i].available)
                        n++;
        return n;
}
EXPORT_SYMBOL_GPL(xfrm_count_auth_supported);

int xfrm_count_enc_supported(void)
{
        int i, n;

        for (i = 0, n = 0; i < ealg_entries(); i++)
                if (ealg_list[i].available)
                        n++;
        return n;
}
EXPORT_SYMBOL_GPL(xfrm_count_enc_supported);

/* Move to common area: it is shared with AH. */

int skb_icv_walk(const struct sk_buff *skb, struct hash_desc *desc,
                 int offset, int len, icv_update_fn_t icv_update)
{
        int start = skb_headlen(skb);
        int i, copy = start - offset;
        struct sk_buff *frag_iter;
        struct scatterlist sg;
        int err;

        /* Checksum header. */
        if (copy > 0) {
                if (copy > len)
                        copy = len;

                sg_init_one(&sg, skb->data + offset, copy);

                err = icv_update(desc, &sg, copy);
                if (unlikely(err))
                        return err;

                if ((len -= copy) == 0)
                        return 0;
                offset += copy;
        }

        for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                int end;

                WARN_ON(start > offset + len);

                end = start + skb_shinfo(skb)->frags[i].size;
                if ((copy = end - offset) > 0) {
                        skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

                        if (copy > len)
                                copy = len;

                        sg_init_table(&sg, 1);
                        sg_set_page(&sg, frag->page, copy,
                                    frag->page_offset + offset-start);

                        err = icv_update(desc, &sg, copy);
                        if (unlikely(err))
                                return err;

                        if (!(len -= copy))
                                return 0;
                        offset += copy;
                }
                start = end;
        }

        skb_walk_frags(skb, frag_iter) {
                int end;

                WARN_ON(start > offset + len);

                end = start + frag_iter->len;
                if ((copy = end - offset) > 0) {
                        if (copy > len)
                                copy = len;
                        err = skb_icv_walk(frag_iter, desc, offset-start,
                                           copy, icv_update);
                        if (unlikely(err))
                                return err;
                        if ((len -= copy) == 0)
                                return 0;
                        offset += copy;
                }
                start = end;
        }
        BUG_ON(len);
        return 0;
}
EXPORT_SYMBOL_GPL(skb_icv_walk);

#if defined(CONFIG_INET_ESP) || defined(CONFIG_INET_ESP_MODULE) || defined(CONFIG_INET6_ESP) || defined(CONFIG_INET6_ESP_MODULE)

void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
{
        if (tail != skb) {
                skb->data_len += len;
                skb->len += len;
        }
        return skb_put(tail, len);
}
EXPORT_SYMBOL_GPL(pskb_put);
#endif