ipv4: IP_TOS and IP_TTL can be specified as ancillary data (f02db315) · Commits · 戴 / test

This patch enables the IP_TTL and IP_TOS values passed from userspace to be stored in the ipcm_cookie struct. Three fields are added to the struct: - the TTL, expressed as __u8. The allowed values are in the [1-255]. A value of 0 means that the TTL is not specified. - the TOS, expressed as __s16. The allowed values are in the range [0,255]. A value of -1 means that the TOS is not specified. - the priority, expressed as a char and computed when handling the ancillary data. Signed-off-by:

Francesco Fusco <ffusco@redhat.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

include/net/ip.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -56,6 +56,9 @@ struct ipcm_cookie {
		int oif;
		struct ip_options_rcu *opt;
		__u8 tx_flags;
		__u8 ttl;
		__s16 tos;
		char priority;
		};

		#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))

net/ipv4/ip_sockglue.c

+19 −1

Original line number	Diff line number	Diff line
		@@ -189,7 +189,7 @@ EXPORT_SYMBOL(ip_cmsg_recv);

		int ip_cmsg_send(struct net net, struct msghdr msg, struct ipcm_cookie *ipc)
		{
		int err;
		int err, val;
		struct cmsghdr *cmsg;

		for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
		@@ -215,6 +215,24 @@ int ip_cmsg_send(struct net net, struct msghdr msg, struct ipcm_cookie *ipc)
		ipc->addr = info->ipi_spec_dst.s_addr;
		break;
		}
		case IP_TTL:
		if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
		return -EINVAL;
		val = (int )CMSG_DATA(cmsg);
		if (val < 1 \|\| val > 255)
		return -EINVAL;
		ipc->ttl = val;
		break;
		case IP_TOS:
		if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
		return -EINVAL;
		val = (int )CMSG_DATA(cmsg);
		if (val < 0 \|\| val > 255)
		return -EINVAL;
		ipc->tos = val;
		ipc->priority = rt_tos2priority(ipc->tos);
		break;

		default:
		return -EINVAL;
		}

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