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136 lines
3.8 KiB
136 lines
3.8 KiB
/* 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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/* 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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/* Designate sk as UDP-Lite socket */ |
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static inline int udplite_sk_init(struct sock *sk) |
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{ |
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udp_init_sock(sk); |
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udp_sk(sk)->pcflag = UDPLITE_BIT; |
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return 0; |
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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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/* Slow-path computation of checksum. Socket is locked. */ |
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static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb) |
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{ |
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const struct udp_sock *up = udp_sk(skb->sk); |
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int cscov = up->len; |
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__wsum csum = 0; |
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if (up->pcflag & UDPLITE_SEND_CC) { |
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/* |
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* Sender has set `partial coverage' option on UDP-Lite socket. |
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* The special case "up->pcslen == 0" signifies full coverage. |
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*/ |
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if (up->pcslen < up->len) { |
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if (0 < up->pcslen) |
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cscov = up->pcslen; |
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udp_hdr(skb)->len = htons(up->pcslen); |
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} |
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/* |
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* NOTE: Causes for the error case `up->pcslen > up->len': |
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* (i) Application error (will not be penalized). |
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* (ii) Payload too big for send buffer: data is split |
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* into several packets, each with its own header. |
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* In this case (e.g. last segment), coverage may |
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* exceed packet length. |
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* Since packets with coverage length > packet length are |
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* illegal, we fall back to the defaults here. |
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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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skb_queue_walk(&sk->sk_write_queue, skb) { |
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const int off = skb_transport_offset(skb); |
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const int len = skb->len - off; |
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csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum); |
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if ((cscov -= len) <= 0) |
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break; |
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} |
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return csum; |
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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 struct udp_sock *up = udp_sk(skb->sk); |
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const int off = skb_transport_offset(skb); |
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int len = skb->len - off; |
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if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) { |
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if (0 < up->pcslen) |
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len = up->pcslen; |
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udp_hdr(skb)->len = htons(up->pcslen); |
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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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int udplite_get_port(struct sock *sk, unsigned short snum, |
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int (*scmp)(const struct sock *, const struct sock *)); |
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#endif /* _UDPLITE_H */
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