[mirror_ubuntu-bionic-kernel.git] / include / net / udplite.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 *	Definitions for the UDP-Lite (RFC 3828) code.
 */
#ifndef _UDPLITE_H
#define _UDPLITE_H

#include <net/ip6_checksum.h>

/* UDP-Lite socket options */
#define UDPLITE_SEND_CSCOV   10 /* sender partial coverage (as sent)      */
#define UDPLITE_RECV_CSCOV   11 /* receiver partial coverage (threshold ) */

extern struct proto 		udplite_prot;
extern struct udp_table		udplite_table;

/*
 *	Checksum computation is all in software, hence simpler getfrag.
 */
static __inline__ int udplite_getfrag(void *from, char *to, int  offset,
				      int len, int odd, struct sk_buff *skb)
{
	struct msghdr *msg = from;
	return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
}

/* Designate sk as UDP-Lite socket */
static inline int udplite_sk_init(struct sock *sk)
{
	udp_init_sock(sk);
	udp_sk(sk)->pcflag = UDPLITE_BIT;
	return 0;
}

/*
 * 	Checksumming routines
 */
static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
{
	u16 cscov;

        /* In UDPv4 a zero checksum means that the transmitter generated no
         * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
         * with a zero checksum field are illegal.                            */
	if (uh->check == 0) {
		net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
		return 1;
	}

	cscov = ntohs(uh->len);

	if (cscov == 0)		 /* Indicates that full coverage is required. */
		;
	else if (cscov < 8  || cscov > skb->len) {
		/*
		 * Coverage length violates RFC 3828: log and discard silently.
		 */
		net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
				    cscov, skb->len);
		return 1;

	} else if (cscov < skb->len) {
        	UDP_SKB_CB(skb)->partial_cov = 1;
		UDP_SKB_CB(skb)->cscov = cscov;
		if (skb->ip_summed == CHECKSUM_COMPLETE)
			skb->ip_summed = CHECKSUM_NONE;
        }

	return 0;
}

/* Slow-path computation of checksum. Socket is locked. */
static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
{
	const struct udp_sock *up = udp_sk(skb->sk);
	int cscov = up->len;
	__wsum csum = 0;

	if (up->pcflag & UDPLITE_SEND_CC) {
		/*
		 * Sender has set `partial coverage' option on UDP-Lite socket.
		 * The special case "up->pcslen == 0" signifies full coverage.
		 */
		if (up->pcslen < up->len) {
			if (0 < up->pcslen)
				cscov = up->pcslen;
			udp_hdr(skb)->len = htons(up->pcslen);
		}
		/*
		 * NOTE: Causes for the error case  `up->pcslen > up->len':
		 *        (i)  Application error (will not be penalized).
		 *       (ii)  Payload too big for send buffer: data is split
		 *             into several packets, each with its own header.
		 *             In this case (e.g. last segment), coverage may
		 *             exceed packet length.
		 *       Since packets with coverage length > packet length are
		 *       illegal, we fall back to the defaults here.
		 */
	}

	skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */

	skb_queue_walk(&sk->sk_write_queue, skb) {
		const int off = skb_transport_offset(skb);
		const int len = skb->len - off;

		csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum);

		if ((cscov -= len) <= 0)
			break;
	}
	return csum;
}

/* Fast-path computation of checksum. Socket may not be locked. */
static inline __wsum udplite_csum(struct sk_buff *skb)
{
	const struct udp_sock *up = udp_sk(skb->sk);
	const int off = skb_transport_offset(skb);
	int len = skb->len - off;

	if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
		if (0 < up->pcslen)
			len = up->pcslen;
		udp_hdr(skb)->len = htons(up->pcslen);
	}
	skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */

	return skb_checksum(skb, off, len, 0);
}

void udplite4_register(void);
int udplite_get_port(struct sock *sk, unsigned short snum,
		     int (*scmp)(const struct sock *, const struct sock *));
#endif	/* _UDPLITE_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
ba4e58ec GR	2	/*
	3	* Definitions for the UDP-Lite (RFC 3828) code.
	4	*/
	5	#ifndef _UDPLITE_H
	6	#define _UDPLITE_H
	7
6bb100b9 DM	8	#include <net/ip6_checksum.h>
6bb100b9 DM	9
ba4e58ec GR	10	/* UDP-Lite socket options */
	11	#define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
	12	#define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
	13
	14	extern struct proto udplite_prot;
645ca708	15	extern struct udp_table udplite_table;
ba4e58ec	16
ba4e58ec GR	17	/*
	18	* Checksum computation is all in software, hence simpler getfrag.
	19	*/
	20	static __inline__ int udplite_getfrag(void from, char to, int offset,
	21	int len, int odd, struct sk_buff *skb)
	22	{
f69e6d13	23	struct msghdr *msg = from;
0b62fca2	24	return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
ba4e58ec GR	25	}
	26
	27	/* Designate sk as UDP-Lite socket */
	28	static inline int udplite_sk_init(struct sock *sk)
	29	{
2276f58a	30	udp_init_sock(sk);
ba4e58ec GR	31	udp_sk(sk)->pcflag = UDPLITE_BIT;
	32	return 0;
	33	}
	34
	35	/*
	36	* Checksumming routines
	37	*/
	38	static inline int udplite_checksum_init(struct sk_buff skb, struct udphdr uh)
	39	{
	40	u16 cscov;
	41
	42	/* In UDPv4 a zero checksum means that the transmitter generated no
	43	* checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
	44	* with a zero checksum field are illegal. */
	45	if (uh->check == 0) {
ba7a46f1	46	net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
ba4e58ec GR	47	return 1;
	48	}
	49
ba4e58ec GR	50	cscov = ntohs(uh->len);
	51
	52	if (cscov == 0) /* Indicates that full coverage is required. */
759e5d00	53	;
ba4e58ec GR	54	else if (cscov < 8 \|\| cscov > skb->len) {
	55	/*
	56	* Coverage length violates RFC 3828: log and discard silently.
	57	*/
ba7a46f1 JP	58	net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
ba7a46f1 JP	59	cscov, skb->len);
ba4e58ec GR	60	return 1;
ba4e58ec GR	61
759e5d00	62	} else if (cscov < skb->len) {
ba4e58ec	63	UDP_SKB_CB(skb)->partial_cov = 1;
759e5d00 HX	64	UDP_SKB_CB(skb)->cscov = cscov;
	65	if (skb->ip_summed == CHECKSUM_COMPLETE)
	66	skb->ip_summed = CHECKSUM_NONE;
	67	}
ba4e58ec GR	68
	69	return 0;
	70	}
	71
f36c23bb GR	72	/* Slow-path computation of checksum. Socket is locked. */
f36c23bb GR	73	static inline __wsum udplite_csum_outgoing(struct sock sk, struct sk_buff skb)
ba4e58ec	74	{
f36c23bb	75	const struct udp_sock *up = udp_sk(skb->sk);
ba4e58ec	76	int cscov = up->len;
f36c23bb	77	__wsum csum = 0;
ba4e58ec	78
f36c23bb GR	79	if (up->pcflag & UDPLITE_SEND_CC) {
	80	/*
	81	* Sender has set `partial coverage' option on UDP-Lite socket.
	82	* The special case "up->pcslen == 0" signifies full coverage.
	83	*/
ba4e58ec	84	if (up->pcslen < up->len) {
f36c23bb GR	85	if (0 < up->pcslen)
	86	cscov = up->pcslen;
	87	udp_hdr(skb)->len = htons(up->pcslen);
ba4e58ec	88	}
f36c23bb GR	89	/*
	90	* NOTE: Causes for the error case `up->pcslen > up->len':
	91	* (i) Application error (will not be penalized).
	92	* (ii) Payload too big for send buffer: data is split
	93	* into several packets, each with its own header.
	94	* In this case (e.g. last segment), coverage may
	95	* exceed packet length.
	96	* Since packets with coverage length > packet length are
	97	* illegal, we fall back to the defaults here.
	98	*/
ba4e58ec	99	}
ba4e58ec GR	100
	101	skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
	102
	103	skb_queue_walk(&sk->sk_write_queue, skb) {
ea2ae17d ACM	104	const int off = skb_transport_offset(skb);
ea2ae17d ACM	105	const int len = skb->len - off;
ba4e58ec GR	106
	107	csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum);
	108
	109	if ((cscov -= len) <= 0)
	110	break;
	111	}
	112	return csum;
	113	}
	114
f36c23bb	115	/* Fast-path computation of checksum. Socket may not be locked. */
f6b9664f HX	116	static inline __wsum udplite_csum(struct sk_buff *skb)
f6b9664f HX	117	{
f36c23bb	118	const struct udp_sock *up = udp_sk(skb->sk);
f6b9664f	119	const int off = skb_transport_offset(skb);
f36c23bb	120	int len = skb->len - off;
f6b9664f	121
f36c23bb GR	122	if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
	123	if (0 < up->pcslen)
	124	len = up->pcslen;
	125	udp_hdr(skb)->len = htons(up->pcslen);
	126	}
f6b9664f HX	127	skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
f6b9664f HX	128
f36c23bb	129	return skb_checksum(skb, off, len, 0);
f6b9664f HX	130	}
f6b9664f HX	131
16073439 JP	132	void udplite4_register(void);
	133	int udplite_get_port(struct sock *sk, unsigned short snum,
	134	int (scmp)(const struct sock , const struct sock *));
ba4e58ec	135	#endif /* _UDPLITE_H */