1 /* SPDX-License-Identifier: GPL-2.0 */
3  *	Definitions for the UDP-Lite (RFC 3828) code.
10 /* UDP-Lite socket options */
18  *	Checksum computation is all in software, hence simpler getfrag.
24 	return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;  in udplite_getfrag()
34         /* In UDPv4 a zero checksum means that the transmitter generated no  in udplite_checksum_init()
35          * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets  in udplite_checksum_init()
36          * with a zero checksum field are illegal.                            */  in udplite_checksum_init()
37 	if (uh->check == 0) {  in udplite_checksum_init()
38 		net_dbg_ratelimited("UDPLite: zeroed checksum field\n");  in udplite_checksum_init()
42 	cscov = ntohs(uh->len);  in udplite_checksum_init()
46 	else if (cscov < 8  || cscov > skb->len) {  in udplite_checksum_init()
51 				    cscov, skb->len);  in udplite_checksum_init()
54 	} else if (cscov < skb->len) {  in udplite_checksum_init()
55         	UDP_SKB_CB(skb)->partial_cov = 1;  in udplite_checksum_init()
56 		UDP_SKB_CB(skb)->cscov = cscov;  in udplite_checksum_init()
57 		if (skb->ip_summed == CHECKSUM_COMPLETE)  in udplite_checksum_init()
58 			skb->ip_summed = CHECKSUM_NONE;  in udplite_checksum_init()
59 		skb->csum_valid = 0;  in udplite_checksum_init()
65 /* Slow-path computation of checksum. Socket is locked. */
68 	const struct udp_sock *up = udp_sk(skb->sk);  in udplite_csum_outgoing()
69 	int cscov = up->len;  in udplite_csum_outgoing()
72 	if (up->pcflag & UDPLITE_SEND_CC) {  in udplite_csum_outgoing()
74 		 * Sender has set `partial coverage' option on UDP-Lite socket.  in udplite_csum_outgoing()
75 		 * The special case "up->pcslen == 0" signifies full coverage.  in udplite_csum_outgoing()
77 		if (up->pcslen < up->len) {  in udplite_csum_outgoing()
78 			if (0 < up->pcslen)  in udplite_csum_outgoing()
79 				cscov = up->pcslen;  in udplite_csum_outgoing()
80 			udp_hdr(skb)->len = htons(up->pcslen);  in udplite_csum_outgoing()
83 		 * NOTE: Causes for the error case  `up->pcslen > up->len':  in udplite_csum_outgoing()
94 	skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */  in udplite_csum_outgoing()
96 	skb_queue_walk(&sk->sk_write_queue, skb) {  in udplite_csum_outgoing()
98 		const int len = skb->len - off;  in udplite_csum_outgoing()
102 		if ((cscov -= len) <= 0)  in udplite_csum_outgoing()
108 /* Fast-path computation of checksum. Socket may not be locked. */
111 	const struct udp_sock *up = udp_sk(skb->sk);  in udplite_csum()
113 	int len = skb->len - off;  in udplite_csum()
115 	if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {  in udplite_csum()
116 		if (0 < up->pcslen)  in udplite_csum()
117 			len = up->pcslen;  in udplite_csum()
118 		udp_hdr(skb)->len = htons(up->pcslen);  in udplite_csum()
120 	skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */  in udplite_csum()