1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Definitions for the UDP-Lite (RFC 3828) code.
8 #include <net/ip6_checksum.h>
11 /* UDP-Lite socket options */
12 #define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
13 #define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
15 extern struct proto udplite_prot;
16 extern struct udp_table udplite_table;
19 * Checksum computation is all in software, hence simpler getfrag.
21 static __inline__ int udplite_getfrag(void *from, char *to, int offset,
22 int len, int odd, struct sk_buff *skb)
24 struct msghdr *msg = from;
25 return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
28 /* Designate sk as UDP-Lite socket */
29 static inline int udplite_sk_init(struct sock *sk)
32 udp_sk(sk)->pcflag = UDPLITE_BIT;
37 * Checksumming routines
39 static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
43 /* In UDPv4 a zero checksum means that the transmitter generated no
44 * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
45 * with a zero checksum field are illegal. */
47 net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
51 cscov = ntohs(uh->len);
53 if (cscov == 0) /* Indicates that full coverage is required. */
55 else if (cscov < 8 || cscov > skb->len) {
57 * Coverage length violates RFC 3828: log and discard silently.
59 net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
63 } else if (cscov < skb->len) {
64 UDP_SKB_CB(skb)->partial_cov = 1;
65 UDP_SKB_CB(skb)->cscov = cscov;
66 if (skb->ip_summed == CHECKSUM_COMPLETE)
67 skb->ip_summed = CHECKSUM_NONE;
74 /* Fast-path computation of checksum. Socket may not be locked. */
75 static inline __wsum udplite_csum(struct sk_buff *skb)
77 const struct udp_sock *up = udp_sk(skb->sk);
78 const int off = skb_transport_offset(skb);
79 int len = skb->len - off;
81 if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
84 udp_hdr(skb)->len = htons(up->pcslen);
86 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
88 return skb_checksum(skb, off, len, 0);
91 void udplite4_register(void);
92 int udplite_get_port(struct sock *sk, unsigned short snum,
93 int (*scmp)(const struct sock *, const struct sock *));
94 #endif /* _UDPLITE_H */