On Wed, Aug 28, 2019 at 10:26 PM Michal Kubecek <mkube...@suse.cz> wrote: > > On Wed, Aug 28, 2019 at 09:36:41PM -0700, Roopa Prabhu wrote: > > > > yes, correct. I mentioned that because I was wondering if we can > > think along the same lines for this API. > > eg > > (a) RTM_NEWLINK always replaces the list attribute > > (b) RTM_SETLINK with NLM_F_APPEND always appends to the list attribute > > (c) RTM_DELLINK with NLM_F_APPEND updates the list attribute > > > > (It could be NLM_F_UPDATE if NLM_F_APPEND sounds weird in the del > > case. I have not looked at the full dellink path if it will work > > neatly..its been a busy day ) > > AFAICS rtnl_dellink() calls nlmsg_parse_deprecated() so that even > current code would ignore any future attribute in RTM_DELLINK message > (any kernel before the strict validation was introduced definitely will) > and it does not seem to check NLM_F_APPEND or NLM_F_UPDATE either. So > unless I missed something, such message would result in deleting the > network device (if possible) with any kernel not implementing the > feature.
ok, ack. yes today it does. I was hinting if that can be changed to support list update with a flag like the RTM_DELLINK AF_BRIDGE does for vlan list del. so to summarize, i think we have discussed the following options to update a netlink list attribute so far: (a) encode an optional attribute/flag in the list attribute in RTM_SETLINK to indicate if it is a add or del (b) Use a flag in RTM_SETLINK and RTM_DELINK to indicate add/del (close to bridge vlan add/del) (c) introduce a separate generic msg type to add/del to a list attribute (IIUC this does need a separate msg type per subsystem or netlink API)
