From 2d4bc93368f5a0ddb57c8c885cdad9c9b7a10ed5 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 12 Apr 2017 14:34:04 +0200 Subject: netlink: extended ACK reporting Add the base infrastructure and UAPI for netlink extended ACK reporting. All "manual" calls to netlink_ack() pass NULL for now and thus don't get extended ACK reporting. Big thanks goes to Pablo Neira Ayuso for not only bringing up the whole topic at netconf (again) but also coming up with the nlattr passing trick and various other ideas. Signed-off-by: Johannes Berg Reviewed-by: David Ahern Signed-off-by: David S. Miller --- net/netlink/af_netlink.c | 71 ++++++++++++++++++++++++++++++++++++++++++------ net/netlink/af_netlink.h | 1 + net/netlink/genetlink.c | 3 +- 3 files changed, 65 insertions(+), 10 deletions(-) (limited to 'net/netlink') diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index fc23244..c156476 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1652,6 +1652,13 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname, nlk->flags &= ~NETLINK_F_CAP_ACK; err = 0; break; + case NETLINK_EXT_ACK: + if (val) + nlk->flags |= NETLINK_F_EXT_ACK; + else + nlk->flags &= ~NETLINK_F_EXT_ACK; + err = 0; + break; default: err = -ENOPROTOOPT; } @@ -1736,6 +1743,15 @@ static int netlink_getsockopt(struct socket *sock, int level, int optname, return -EFAULT; err = 0; break; + case NETLINK_EXT_ACK: + if (len < sizeof(int)) + return -EINVAL; + len = sizeof(int); + val = nlk->flags & NETLINK_F_EXT_ACK ? 1 : 0; + if (put_user(len, optlen) || put_user(val, optval)) + return -EFAULT; + err = 0; + break; default: err = -ENOPROTOOPT; } @@ -2267,21 +2283,40 @@ error_free: } EXPORT_SYMBOL(__netlink_dump_start); -void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) +void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, + const struct netlink_ext_ack *extack) { struct sk_buff *skb; struct nlmsghdr *rep; struct nlmsgerr *errmsg; size_t payload = sizeof(*errmsg); + size_t tlvlen = 0; struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk); + unsigned int flags = 0; /* Error messages get the original request appened, unless the user - * requests to cap the error message. + * requests to cap the error message, and get extra error data if + * requested. */ - if (!(nlk->flags & NETLINK_F_CAP_ACK) && err) - payload += nlmsg_len(nlh); + if (err) { + if (!(nlk->flags & NETLINK_F_CAP_ACK)) + payload += nlmsg_len(nlh); + else + flags |= NLM_F_CAPPED; + if (nlk->flags & NETLINK_F_EXT_ACK && extack) { + if (extack->_msg) + tlvlen += nla_total_size(strlen(extack->_msg) + 1); + if (extack->bad_attr) + tlvlen += nla_total_size(sizeof(u32)); + } + } else { + flags |= NLM_F_CAPPED; + } - skb = nlmsg_new(payload, GFP_KERNEL); + if (tlvlen) + flags |= NLM_F_ACK_TLVS; + + skb = nlmsg_new(payload + tlvlen, GFP_KERNEL); if (!skb) { struct sock *sk; @@ -2297,17 +2332,35 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) } rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, - NLMSG_ERROR, payload, 0); + NLMSG_ERROR, payload, flags); errmsg = nlmsg_data(rep); errmsg->error = err; memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh)); + + if (err && nlk->flags & NETLINK_F_EXT_ACK && extack) { + if (extack->_msg) + WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, + extack->_msg)); + if (extack->bad_attr && + !WARN_ON((u8 *)extack->bad_attr < in_skb->data || + (u8 *)extack->bad_attr >= in_skb->data + + in_skb->len)) + WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS, + (u8 *)extack->bad_attr - + in_skb->data)); + } + + nlmsg_end(skb, rep); + netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT); } EXPORT_SYMBOL(netlink_ack); int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, - struct nlmsghdr *)) + struct nlmsghdr *, + struct netlink_ext_ack *)) { + struct netlink_ext_ack extack = {}; struct nlmsghdr *nlh; int err; @@ -2328,13 +2381,13 @@ int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, if (nlh->nlmsg_type < NLMSG_MIN_TYPE) goto ack; - err = cb(skb, nlh); + err = cb(skb, nlh, &extack); if (err == -EINTR) goto skip; ack: if (nlh->nlmsg_flags & NLM_F_ACK || err) - netlink_ack(skb, nlh, err); + netlink_ack(skb, nlh, err, &extack); skip: msglen = NLMSG_ALIGN(nlh->nlmsg_len); diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h index f792f8d..3490f24 100644 --- a/net/netlink/af_netlink.h +++ b/net/netlink/af_netlink.h @@ -13,6 +13,7 @@ #define NETLINK_F_RECV_NO_ENOBUFS 0x8 #define NETLINK_F_LISTEN_ALL_NSID 0x10 #define NETLINK_F_CAP_ACK 0x20 +#define NETLINK_F_EXT_ACK 0x40 #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8) #define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long)) diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 92e0981..57b2e36 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -605,7 +605,8 @@ out: return err; } -static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) +static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, + struct netlink_ext_ack *extack) { const struct genl_family *family; int err; -- cgit v1.1