1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Definitions for the UDP-Lite (RFC 3828) code.
8 #include <net/ip6_checksum.h>
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 ) */
14 extern struct proto udplite_prot;
15 extern struct udp_table udplite_table;
18 * Checksum computation is all in software, hence simpler getfrag.
20 static __inline__ int udplite_getfrag(void *from, char *to, int offset,
21 int len, int odd, struct sk_buff *skb)
23 struct msghdr *msg = from;
24 return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
27 /* Designate sk as UDP-Lite socket */
28 static inline int udplite_sk_init(struct sock *sk)
31 udp_sk(sk)->pcflag = UDPLITE_BIT;
36 * Checksumming routines
38 static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
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. */
46 net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
50 cscov = ntohs(uh->len);
52 if (cscov == 0) /* Indicates that full coverage is required. */
54 else if (cscov < 8 || cscov > skb->len) {
56 * Coverage length violates RFC 3828: log and discard silently.
58 net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
62 } else if (cscov < skb->len) {
63 UDP_SKB_CB(skb)->partial_cov = 1;
64 UDP_SKB_CB(skb)->cscov = cscov;
65 if (skb->ip_summed == CHECKSUM_COMPLETE)
66 skb->ip_summed = CHECKSUM_NONE;
73 /* Fast-path computation of checksum. Socket may not be locked. */
74 static inline __wsum udplite_csum(struct sk_buff *skb)
76 const struct udp_sock *up = udp_sk(skb->sk);
77 const int off = skb_transport_offset(skb);
78 int len = skb->len - off;
80 if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
83 udp_hdr(skb)->len = htons(up->pcslen);
85 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
87 return skb_checksum(skb, off, len, 0);
90 void udplite4_register(void);
91 int udplite_get_port(struct sock *sk, unsigned short snum,
92 int (*scmp)(const struct sock *, const struct sock *));
93 #endif /* _UDPLITE_H */