datagram.c

linux 内核源代码

	/* Reset and regenerate socket error */
	spin_lock_bh(&sk->sk_error_queue.lock);
	sk->sk_err = 0;
	if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
		sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
		spin_unlock_bh(&sk->sk_error_queue.lock);
		sk->sk_error_report(sk);
	} else {
		spin_unlock_bh(&sk->sk_error_queue.lock);
	}

out_free_skb:
	kfree_skb(skb);
out:
	return err;
}



int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct inet6_skb_parm *opt = IP6CB(skb);
	unsigned char *nh = skb_network_header(skb);

	if (np->rxopt.bits.rxinfo) {
		struct in6_pktinfo src_info;

		src_info.ipi6_ifindex = opt->iif;
		ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
		put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
	}

	if (np->rxopt.bits.rxhlim) {
		int hlim = ipv6_hdr(skb)->hop_limit;
		put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
	}

	if (np->rxopt.bits.rxtclass) {
		int tclass = (ntohl(*(__be32 *)ipv6_hdr(skb)) >> 20) & 0xff;
		put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
	}

	if (np->rxopt.bits.rxflow && (*(__be32 *)nh & IPV6_FLOWINFO_MASK)) {
		__be32 flowinfo = *(__be32 *)nh & IPV6_FLOWINFO_MASK;
		put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
	}

	/* HbH is allowed only once */
	if (np->rxopt.bits.hopopts && opt->hop) {
		u8 *ptr = nh + opt->hop;
		put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
	}

	if (opt->lastopt &&
	    (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
		/*
		 * Silly enough, but we need to reparse in order to
		 * report extension headers (except for HbH)
		 * in order.
		 *
		 * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
		 * (and WILL NOT be) defined because
		 * IPV6_RECVDSTOPTS is more generic. --yoshfuji
		 */
		unsigned int off = sizeof(struct ipv6hdr);
		u8 nexthdr = ipv6_hdr(skb)->nexthdr;

		while (off <= opt->lastopt) {
			unsigned len;
			u8 *ptr = nh + off;

			switch(nexthdr) {
			case IPPROTO_DSTOPTS:
				nexthdr = ptr[0];
				len = (ptr[1] + 1) << 3;
				if (np->rxopt.bits.dstopts)
					put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
				break;
			case IPPROTO_ROUTING:
				nexthdr = ptr[0];
				len = (ptr[1] + 1) << 3;
				if (np->rxopt.bits.srcrt)
					put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
				break;
			case IPPROTO_AH:
				nexthdr = ptr[0];
				len = (ptr[1] + 2) << 2;
				break;
			default:
				nexthdr = ptr[0];
				len = (ptr[1] + 1) << 3;
				break;
			}

			off += len;
		}
	}

	/* socket options in old style */
	if (np->rxopt.bits.rxoinfo) {
		struct in6_pktinfo src_info;

		src_info.ipi6_ifindex = opt->iif;
		ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
		put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
	}
	if (np->rxopt.bits.rxohlim) {
		int hlim = ipv6_hdr(skb)->hop_limit;
		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
	}
	if (np->rxopt.bits.ohopopts && opt->hop) {
		u8 *ptr = nh + opt->hop;
		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
	}
	if (np->rxopt.bits.odstopts && opt->dst0) {
		u8 *ptr = nh + opt->dst0;
		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
	}
	if (np->rxopt.bits.osrcrt && opt->srcrt) {
		struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
		put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
	}
	if (np->rxopt.bits.odstopts && opt->dst1) {
		u8 *ptr = nh + opt->dst1;
		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
	}
	return 0;
}

int datagram_send_ctl(struct msghdr *msg, struct flowi *fl,
		      struct ipv6_txoptions *opt,
		      int *hlimit, int *tclass)
{
	struct in6_pktinfo *src_info;
	struct cmsghdr *cmsg;
	struct ipv6_rt_hdr *rthdr;
	struct ipv6_opt_hdr *hdr;
	int len;
	int err = 0;

	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
		int addr_type;
		struct net_device *dev = NULL;

		if (!CMSG_OK(msg, cmsg)) {
			err = -EINVAL;
			goto exit_f;
		}

		if (cmsg->cmsg_level != SOL_IPV6)
			continue;

		switch (cmsg->cmsg_type) {
		case IPV6_PKTINFO:
		case IPV6_2292PKTINFO:
			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
				err = -EINVAL;
				goto exit_f;
			}

			src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);

			if (src_info->ipi6_ifindex) {
				if (fl->oif && src_info->ipi6_ifindex != fl->oif)
					return -EINVAL;
				fl->oif = src_info->ipi6_ifindex;
			}

			addr_type = ipv6_addr_type(&src_info->ipi6_addr);

			if (addr_type == IPV6_ADDR_ANY)
				break;

			if (addr_type & IPV6_ADDR_LINKLOCAL) {
				if (!src_info->ipi6_ifindex)
					return -EINVAL;
				else {
					dev = dev_get_by_index(&init_net, src_info->ipi6_ifindex);
					if (!dev)
						return -ENODEV;
				}
			}
			if (!ipv6_chk_addr(&src_info->ipi6_addr, dev, 0)) {
				if (dev)
					dev_put(dev);
				err = -EINVAL;
				goto exit_f;
			}
			if (dev)
				dev_put(dev);

			ipv6_addr_copy(&fl->fl6_src, &src_info->ipi6_addr);
			break;

		case IPV6_FLOWINFO:
			if (cmsg->cmsg_len < CMSG_LEN(4)) {
				err = -EINVAL;
				goto exit_f;
			}

			if (fl->fl6_flowlabel&IPV6_FLOWINFO_MASK) {
				if ((fl->fl6_flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
					err = -EINVAL;
					goto exit_f;
				}
			}
			fl->fl6_flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
			break;

		case IPV6_2292HOPOPTS:
		case IPV6_HOPOPTS:
			if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
				err = -EINVAL;
				goto exit_f;
			}

			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
			len = ((hdr->hdrlen + 1) << 3);
			if (cmsg->cmsg_len < CMSG_LEN(len)) {
				err = -EINVAL;
				goto exit_f;
			}
			if (!capable(CAP_NET_RAW)) {
				err = -EPERM;
				goto exit_f;
			}
			opt->opt_nflen += len;
			opt->hopopt = hdr;
			break;

		case IPV6_2292DSTOPTS:
			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
				err = -EINVAL;
				goto exit_f;
			}

			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
			len = ((hdr->hdrlen + 1) << 3);
			if (cmsg->cmsg_len < CMSG_LEN(len)) {
				err = -EINVAL;
				goto exit_f;
			}
			if (!capable(CAP_NET_RAW)) {
				err = -EPERM;
				goto exit_f;
			}
			if (opt->dst1opt) {
				err = -EINVAL;
				goto exit_f;
			}
			opt->opt_flen += len;
			opt->dst1opt = hdr;
			break;

		case IPV6_DSTOPTS:
		case IPV6_RTHDRDSTOPTS:
			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
				err = -EINVAL;
				goto exit_f;
			}

			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
			len = ((hdr->hdrlen + 1) << 3);
			if (cmsg->cmsg_len < CMSG_LEN(len)) {
				err = -EINVAL;
				goto exit_f;
			}
			if (!capable(CAP_NET_RAW)) {
				err = -EPERM;
				goto exit_f;
			}
			if (cmsg->cmsg_type == IPV6_DSTOPTS) {
				opt->opt_flen += len;
				opt->dst1opt = hdr;
			} else {
				opt->opt_nflen += len;
				opt->dst0opt = hdr;
			}
			break;

		case IPV6_2292RTHDR:
		case IPV6_RTHDR:
			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
				err = -EINVAL;
				goto exit_f;
			}

			rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);

			switch (rthdr->type) {
#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
			case IPV6_SRCRT_TYPE_2:
				break;
#endif
			default:
				err = -EINVAL;
				goto exit_f;
			}

			len = ((rthdr->hdrlen + 1) << 3);

			if (cmsg->cmsg_len < CMSG_LEN(len)) {
				err = -EINVAL;
				goto exit_f;
			}

			/* segments left must also match */
			if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
				err = -EINVAL;
				goto exit_f;
			}

			opt->opt_nflen += len;
			opt->srcrt = rthdr;

			if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
				int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);

				opt->opt_nflen += dsthdrlen;
				opt->dst0opt = opt->dst1opt;
				opt->dst1opt = NULL;
				opt->opt_flen -= dsthdrlen;
			}

			break;

		case IPV6_2292HOPLIMIT:
		case IPV6_HOPLIMIT:
			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
				err = -EINVAL;
				goto exit_f;
			}

			*hlimit = *(int *)CMSG_DATA(cmsg);
			break;

		case IPV6_TCLASS:
		    {
			int tc;

			err = -EINVAL;
			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
				goto exit_f;
			}

			tc = *(int *)CMSG_DATA(cmsg);
			if (tc < -1 || tc > 0xff)
				goto exit_f;

			err = 0;
			*tclass = tc;

			break;
		    }
		default:
			LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
				       cmsg->cmsg_type);
			err = -EINVAL;
			break;
		}
	}

exit_f:
	return err;
}