89 lines
2.3 KiB
C
89 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Definitions for the UDP-Lite (RFC 3828) code.
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*/
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#ifndef _UDPLITE_H
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#define _UDPLITE_H
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#include <net/ip6_checksum.h>
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#include <net/udp.h>
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/* UDP-Lite socket options */
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#define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
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#define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
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extern struct proto udplite_prot;
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extern struct udp_table udplite_table;
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/*
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* Checksum computation is all in software, hence simpler getfrag.
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*/
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static __inline__ int udplite_getfrag(void *from, char *to, int offset,
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int len, int odd, struct sk_buff *skb)
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{
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struct msghdr *msg = from;
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return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
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}
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/*
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* Checksumming routines
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*/
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static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
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{
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u16 cscov;
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/* In UDPv4 a zero checksum means that the transmitter generated no
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* checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
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* with a zero checksum field are illegal. */
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if (uh->check == 0) {
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net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
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return 1;
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}
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cscov = ntohs(uh->len);
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if (cscov == 0) /* Indicates that full coverage is required. */
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;
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else if (cscov < 8 || cscov > skb->len) {
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/*
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* Coverage length violates RFC 3828: log and discard silently.
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*/
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net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
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cscov, skb->len);
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return 1;
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} else if (cscov < skb->len) {
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UDP_SKB_CB(skb)->partial_cov = 1;
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UDP_SKB_CB(skb)->cscov = cscov;
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if (skb->ip_summed == CHECKSUM_COMPLETE)
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skb->ip_summed = CHECKSUM_NONE;
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skb->csum_valid = 0;
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}
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return 0;
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}
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/* Fast-path computation of checksum. Socket may not be locked. */
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static inline __wsum udplite_csum(struct sk_buff *skb)
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{
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const int off = skb_transport_offset(skb);
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const struct sock *sk = skb->sk;
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int len = skb->len - off;
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if (udp_test_bit(UDPLITE_SEND_CC, sk)) {
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u16 pcslen = READ_ONCE(udp_sk(sk)->pcslen);
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if (pcslen < len) {
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if (pcslen > 0)
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len = pcslen;
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udp_hdr(skb)->len = htons(pcslen);
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}
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}
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skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
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return skb_checksum(skb, off, len, 0);
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}
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void udplite4_register(void);
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#endif /* _UDPLITE_H */
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