On Sat, Jun 24, 2017 at 04:36:34AM +0300, Dmitry V. Levin wrote:
> On Sat, Jun 24, 2017 at 09:06:06AM +0800, JingPiao Chen wrote:
> > static int
> > print_nlmsghdr(struct tcb *tcp,
> > const int fd,
> > int family,
> > const struct nlmsghdr *const nlmsghdr)
> > {
> > ...
> > const int hdr_family = (nlmsghdr->nlmsg_type < NLMSG_MIN_TYPE)
> > ? NL_FAMILY_DEFAULT
> > : (family != NL_FAMILY_DEFAULT
> > ? family : get_fd_nl_family(tcp, fd));
>
> Feel free to change this if NLMSG_DONE needs a family specific decoding.
I have send a patch. I've also thought about rewriting NLMSG_DONE,
because only three family send useful data: drivers/connector/connector.c,
drivers/infiniband/core/iwpm_util.c and net/netfilter/nfnetlink_log.c.
In the end, I think it's good enough, but I want to ask your opinion.
$ git grep "NLMSG_DONE"
drivers/connector/connector.c: nlh = nlmsg_put(skb, 0, msg->seq, NLMSG_DONE,
size, 0);
drivers/infiniband/core/iwpm_util.c: nlh->nlmsg_type = NLMSG_DONE;
These two family I do not understand what they send.
net/netfilter/nfnetlink_log.c:
static void
__nfulnl_send(struct nfulnl_instance *inst)
{
if (inst->qlen > 1) {
struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
NLMSG_DONE,
sizeof(struct nfgenmsg),
0);
if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
inst->skb->len, skb_tailroom(inst->skb))) {
kfree_skb(inst->skb);
goto out;
}
}
nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
MSG_DONTWAIT);
out:
inst->qlen = 0;
inst->skb = NULL;
}
It allocate struct nfgenmsg, but do not initialize it.
Following family data length is zero. Default decoder can handle them.
drivers/net/team/team.c: nlh = nlmsg_put(skb, portid, seq, NLMSG_DONE, 0, flags
| NLM_F_MULTI);
drivers/scsi/scsi_transport_iscsi.c: int t = done ? NLMSG_DONE : type;
static void
iscsi_if_rx(struct sk_buff *skb)
{
...
err = iscsi_if_send_reply(group, nlh->nlmsg_seq,
nlh->nlmsg_type, 0, 0, ev, sizeof(*ev));
...
}
kernel/audit.c: int t = done ? NLMSG_DONE : type;
kernel/auditfilter.c:
static void audit_list_rules(int seq, struct sk_buff_head *q)
{
...
skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
...
}
net/core/devlink.c: NLMSG_DONE, 0, flags | NLM_F_MULTI);
net/core/devlink.c: NLMSG_DONE, 0, flags | NLM_F_MULTI);
net/core/devlink.c: NLMSG_DONE, 0, flags | NLM_F_MULTI);
--
JingPiao Chen
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