cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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udplite.h (2577B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2/*
      3 *	Definitions for the UDP-Lite (RFC 3828) code.
      4 */
      5#ifndef _UDPLITE_H
      6#define _UDPLITE_H
      7
      8#include <net/ip6_checksum.h>
      9
     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 ) */
     13
     14extern struct proto 		udplite_prot;
     15extern struct udp_table		udplite_table;
     16
     17/*
     18 *	Checksum computation is all in software, hence simpler getfrag.
     19 */
     20static __inline__ int udplite_getfrag(void *from, char *to, int  offset,
     21				      int len, int odd, struct sk_buff *skb)
     22{
     23	struct msghdr *msg = from;
     24	return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
     25}
     26
     27/* Designate sk as UDP-Lite socket */
     28static inline int udplite_sk_init(struct sock *sk)
     29{
     30	udp_init_sock(sk);
     31	udp_sk(sk)->pcflag = UDPLITE_BIT;
     32	return 0;
     33}
     34
     35/*
     36 * 	Checksumming routines
     37 */
     38static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
     39{
     40	u16 cscov;
     41
     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.                            */
     45	if (uh->check == 0) {
     46		net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
     47		return 1;
     48	}
     49
     50	cscov = ntohs(uh->len);
     51
     52	if (cscov == 0)		 /* Indicates that full coverage is required. */
     53		;
     54	else if (cscov < 8  || cscov > skb->len) {
     55		/*
     56		 * Coverage length violates RFC 3828: log and discard silently.
     57		 */
     58		net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
     59				    cscov, skb->len);
     60		return 1;
     61
     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;
     67		skb->csum_valid = 0;
     68        }
     69
     70	return 0;
     71}
     72
     73/* Fast-path computation of checksum. Socket may not be locked. */
     74static inline __wsum udplite_csum(struct sk_buff *skb)
     75{
     76	const struct udp_sock *up = udp_sk(skb->sk);
     77	const int off = skb_transport_offset(skb);
     78	int len = skb->len - off;
     79
     80	if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
     81		if (0 < up->pcslen)
     82			len = up->pcslen;
     83		udp_hdr(skb)->len = htons(up->pcslen);
     84	}
     85	skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */
     86
     87	return skb_checksum(skb, off, len, 0);
     88}
     89
     90void udplite4_register(void);
     91int udplite_get_port(struct sock *sk, unsigned short snum,
     92		     int (*scmp)(const struct sock *, const struct sock *));
     93#endif	/* _UDPLITE_H */