/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation
 */

#ifndef _RTE_IP_FRAG_H_
#define _RTE_IP_FRAG_H_

/**
 * @file
 * RTE IP Fragmentation and Reassembly
 *
 * Implementation of IP packet fragmentation and reassembly.
 */

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>
#include <stdio.h>

#include <rte_config.h>
#include <rte_malloc.h>
#include <rte_memory.h>
#include <rte_ip.h>
#include <rte_byteorder.h>

struct rte_mbuf;

enum {
	IP_LAST_FRAG_IDX,    /**< index of last fragment */
	IP_FIRST_FRAG_IDX,   /**< index of first fragment */
	IP_MIN_FRAG_NUM,     /**< minimum number of fragments */
	IP_MAX_FRAG_NUM = RTE_LIBRTE_IP_FRAG_MAX_FRAG,
	/**< maximum number of fragments per packet */
};

/** @internal fragmented mbuf */
struct ip_frag {
	uint16_t ofs;          /**< offset into the packet */
	uint16_t len;          /**< length of fragment */
	struct rte_mbuf *mb;   /**< fragment mbuf */
};

/** @internal <src addr, dst_addr, id> to uniquely identify fragmented datagram. */
struct ip_frag_key {
	uint64_t src_dst[4];
	/**< src and dst address, only first 8 bytes used for IPv4 */
	RTE_STD_C11
	union {
		uint64_t id_key_len; /**< combined for easy fetch */
		__extension__
		struct {
			uint32_t id;       /**< packet id */
			uint32_t key_len;  /**< src/dst key length */
		};
	};
};

/**
 * @internal Fragmented packet to reassemble.
 * First two entries in the frags[] array are for the last and first fragments.
 */
struct ip_frag_pkt {
	TAILQ_ENTRY(ip_frag_pkt) lru;   /**< LRU list */
	struct ip_frag_key key;           /**< fragmentation key */
	uint64_t             start;       /**< creation timestamp */
	uint32_t             total_size;  /**< expected reassembled size */
	uint32_t             frag_size;   /**< size of fragments received */
	uint32_t             last_idx;    /**< index of next entry to fill */
	struct ip_frag       frags[IP_MAX_FRAG_NUM]; /**< fragments */
} __rte_cache_aligned;

#define IP_FRAG_DEATH_ROW_LEN 32 /**< death row size (in packets) */

/* death row size in mbufs */
#define IP_FRAG_DEATH_ROW_MBUF_LEN (IP_FRAG_DEATH_ROW_LEN * (IP_MAX_FRAG_NUM + 1))

/** mbuf death row (packets to be freed) */
struct rte_ip_frag_death_row {
	uint32_t cnt;          /**< number of mbufs currently on death row */
	struct rte_mbuf *row[IP_FRAG_DEATH_ROW_MBUF_LEN];
	/**< mbufs to be freed */
};

TAILQ_HEAD(ip_pkt_list, ip_frag_pkt); /**< @internal fragments tailq */

/** fragmentation table statistics */
struct ip_frag_tbl_stat {
	uint64_t find_num;      /**< total # of find/insert attempts. */
	uint64_t add_num;       /**< # of add ops. */
	uint64_t del_num;       /**< # of del ops. */
	uint64_t reuse_num;     /**< # of reuse (del/add) ops. */
	uint64_t fail_total;    /**< total # of add failures. */
	uint64_t fail_nospace;  /**< # of 'no space' add failures. */
} __rte_cache_aligned;

/** fragmentation table */
struct rte_ip_frag_tbl {
	uint64_t             max_cycles;      /**< ttl for table entries. */
	uint32_t             entry_mask;      /**< hash value mask. */
	uint32_t             max_entries;     /**< max entries allowed. */
	uint32_t             use_entries;     /**< entries in use. */
	uint32_t             bucket_entries;  /**< hash associativity. */
	uint32_t             nb_entries;      /**< total size of the table. */
	uint32_t             nb_buckets;      /**< num of associativity lines. */
	struct ip_frag_pkt *last;         /**< last used entry. */
	struct ip_pkt_list lru;           /**< LRU list for table entries. */
	struct ip_frag_tbl_stat stat;     /**< statistics counters. */
	__extension__ struct ip_frag_pkt pkt[0]; /**< hash table. */
};

/** IPv6 fragment extension header */
#define	RTE_IPV6_EHDR_MF_SHIFT			0
#define	RTE_IPV6_EHDR_MF_MASK			1
#define	RTE_IPV6_EHDR_FO_SHIFT			3
#define	RTE_IPV6_EHDR_FO_MASK			(~((1 << RTE_IPV6_EHDR_FO_SHIFT) - 1))
#define	RTE_IPV6_EHDR_FO_ALIGN			(1 << RTE_IPV6_EHDR_FO_SHIFT)

#define RTE_IPV6_FRAG_USED_MASK			\
	(RTE_IPV6_EHDR_MF_MASK | RTE_IPV6_EHDR_FO_MASK)

#define RTE_IPV6_GET_MF(x)				((x) & RTE_IPV6_EHDR_MF_MASK)
#define RTE_IPV6_GET_FO(x)				((x) >> RTE_IPV6_EHDR_FO_SHIFT)

#define RTE_IPV6_SET_FRAG_DATA(fo, mf)	\
	(((fo) & RTE_IPV6_EHDR_FO_MASK) | ((mf) & RTE_IPV6_EHDR_MF_MASK))

struct ipv6_extension_fragment {
	uint8_t next_header;            /**< Next header type */
	uint8_t reserved;               /**< Reserved */
	uint16_t frag_data;             /**< All fragmentation data */
	uint32_t id;                    /**< Packet ID */
} __attribute__((__packed__));



/**
 * Create a new IP fragmentation table.
 *
 * @param bucket_num
 *   Number of buckets in the hash table.
 * @param bucket_entries
 *   Number of entries per bucket (e.g. hash associativity).
 *   Should be power of two.
 * @param max_entries
 *   Maximum number of entries that could be stored in the table.
 *   The value should be less or equal then bucket_num * bucket_entries.
 * @param max_cycles
 *   Maximum TTL in cycles for each fragmented packet.
 * @param socket_id
 *   The *socket_id* argument is the socket identifier in the case of
 *   NUMA. The value can be *SOCKET_ID_ANY* if there is no NUMA constraints.
 * @return
 *   The pointer to the new allocated fragmentation table, on success. NULL on error.
 */
struct rte_ip_frag_tbl * rte_ip_frag_table_create(uint32_t bucket_num,
		uint32_t bucket_entries,  uint32_t max_entries,
		uint64_t max_cycles, int socket_id);

/**
 * Free allocated IP fragmentation table.
 *
 * @param tbl
 *   Fragmentation table to free.
 */
void
rte_ip_frag_table_destroy(struct rte_ip_frag_tbl *tbl);

/**
 * This function implements the fragmentation of IPv6 packets.
 *
 * @param pkt_in
 *   The input packet.
 * @param pkts_out
 *   Array storing the output fragments.
 * @param nb_pkts_out
 *   Number of fragments.
 * @param mtu_size
 *   Size in bytes of the Maximum Transfer Unit (MTU) for the outgoing IPv6
 *   datagrams. This value includes the size of the IPv6 header.
 * @param pool_direct
 *   MBUF pool used for allocating direct buffers for the output fragments.
 * @param pool_indirect
 *   MBUF pool used for allocating indirect buffers for the output fragments.
 * @return
 *   Upon successful completion - number of output fragments placed
 *   in the pkts_out array.
 *   Otherwise - (-1) * errno.
 */
int32_t
rte_ipv6_fragment_packet(struct rte_mbuf *pkt_in,
		struct rte_mbuf **pkts_out,
		uint16_t nb_pkts_out,
		uint16_t mtu_size,
		struct rte_mempool *pool_direct,
		struct rte_mempool *pool_indirect);

/**
 * This function implements reassembly of fragmented IPv6 packets.
 * Incoming mbuf should have its l2_len/l3_len fields setup correctly.
 *
 * @param tbl
 *   Table where to lookup/add the fragmented packet.
 * @param dr
 *   Death row to free buffers to
 * @param mb
 *   Incoming mbuf with IPv6 fragment.
 * @param tms
 *   Fragment arrival timestamp.
 * @param ip_hdr
 *   Pointer to the IPv6 header.
 * @param frag_hdr
 *   Pointer to the IPv6 fragment extension header.
 * @return
 *   Pointer to mbuf for reassembled packet, or NULL if:
 *   - an error occurred.
 *   - not all fragments of the packet are collected yet.
 */
struct rte_mbuf *rte_ipv6_frag_reassemble_packet(struct rte_ip_frag_tbl *tbl,
		struct rte_ip_frag_death_row *dr,
		struct rte_mbuf *mb, uint64_t tms, struct rte_ipv6_hdr *ip_hdr,
		struct ipv6_extension_fragment *frag_hdr);

/**
 * Return a pointer to the packet's fragment header, if found.
 * It only looks at the extension header that's right after the fixed IPv6
 * header, and doesn't follow the whole chain of extension headers.
 *
 * @param hdr
 *   Pointer to the IPv6 header.
 * @return
 *   Pointer to the IPv6 fragment extension header, or NULL if it's not
 *   present.
 */
static inline struct ipv6_extension_fragment *
rte_ipv6_frag_get_ipv6_fragment_header(struct rte_ipv6_hdr *hdr)
{
	if (hdr->proto == IPPROTO_FRAGMENT) {
		return (struct ipv6_extension_fragment *) ++hdr;
	}
	else
		return NULL;
}

/**
 * IPv4 fragmentation.
 *
 * This function implements the fragmentation of IPv4 packets.
 *
 * @param pkt_in
 *   The input packet.
 * @param pkts_out
 *   Array storing the output fragments.
 * @param nb_pkts_out
 *   Number of fragments.
 * @param mtu_size
 *   Size in bytes of the Maximum Transfer Unit (MTU) for the outgoing IPv4
 *   datagrams. This value includes the size of the IPv4 header.
 * @param pool_direct
 *   MBUF pool used for allocating direct buffers for the output fragments.
 * @param pool_indirect
 *   MBUF pool used for allocating indirect buffers for the output fragments.
 * @return
 *   Upon successful completion - number of output fragments placed
 *   in the pkts_out array.
 *   Otherwise - (-1) * errno.
 */
int32_t rte_ipv4_fragment_packet(struct rte_mbuf *pkt_in,
			struct rte_mbuf **pkts_out,
			uint16_t nb_pkts_out, uint16_t mtu_size,
			struct rte_mempool *pool_direct,
			struct rte_mempool *pool_indirect);

/**
 * This function implements reassembly of fragmented IPv4 packets.
 * Incoming mbufs should have its l2_len/l3_len fields setup correctly.
 *
 * @param tbl
 *   Table where to lookup/add the fragmented packet.
 * @param dr
 *   Death row to free buffers to
 * @param mb
 *   Incoming mbuf with IPv4 fragment.
 * @param tms
 *   Fragment arrival timestamp.
 * @param ip_hdr
 *   Pointer to the IPV4 header inside the fragment.
 * @return
 *   Pointer to mbuf for reassembled packet, or NULL if:
 *   - an error occurred.
 *   - not all fragments of the packet are collected yet.
 */
struct rte_mbuf * rte_ipv4_frag_reassemble_packet(struct rte_ip_frag_tbl *tbl,
		struct rte_ip_frag_death_row *dr,
		struct rte_mbuf *mb, uint64_t tms, struct rte_ipv4_hdr *ip_hdr);

/**
 * Check if the IPv4 packet is fragmented
 *
 * @param hdr
 *   IPv4 header of the packet
 * @return
 *   1 if fragmented, 0 if not fragmented
 */
static inline int
rte_ipv4_frag_pkt_is_fragmented(const struct rte_ipv4_hdr *hdr)
{
	uint16_t flag_offset, ip_flag, ip_ofs;

	flag_offset = rte_be_to_cpu_16(hdr->fragment_offset);
	ip_ofs = (uint16_t)(flag_offset & RTE_IPV4_HDR_OFFSET_MASK);
	ip_flag = (uint16_t)(flag_offset & RTE_IPV4_HDR_MF_FLAG);

	return ip_flag != 0 || ip_ofs  != 0;
}

/**
 * Free mbufs on a given death row.
 *
 * @param dr
 *   Death row to free mbufs in.
 * @param prefetch
 *   How many buffers to prefetch before freeing.
 */
void rte_ip_frag_free_death_row(struct rte_ip_frag_death_row *dr,
		uint32_t prefetch);


/**
 * Dump fragmentation table statistics to file.
 *
 * @param f
 *   File to dump statistics to
 * @param tbl
 *   Fragmentation table to dump statistics from
 */
void
rte_ip_frag_table_statistics_dump(FILE * f, const struct rte_ip_frag_tbl *tbl);

/**
 * Delete expired fragments
 *
 * @param tbl
 *   Table to delete expired fragments from
 * @param dr
 *   Death row to free buffers to
 * @param tms
 *   Current timestamp
 */
__rte_experimental
void
rte_frag_table_del_expired_entries(struct rte_ip_frag_tbl *tbl,
	struct rte_ip_frag_death_row *dr, uint64_t tms);

#ifdef __cplusplus
}
#endif

#endif /* _RTE_IP_FRAG_H_ */
