[libvirt] [PATCHv4 2/2] util: netlink: Add wrapper macros to make virNetlinkNewLink more readable

This patch adds wrapper macros around nla_nest_[start|end] and nla_put which can make virNetlinkNewLink more readable. Signed-off-by: Shi Lei <shi_lei(a)massclouds.com&gt; --- src/util/virnetlink.c | 35 +++++++++++------------------------ src/util/virnetlink.h | 23 +++++++++++++++++++++++ 2 files changed, 34 insertions(+), 24 deletions(-) diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c index 815bbee..b424b1b 100644 --- a/src/util/virnetlink.c +++ b/src/util/virnetlink.c @@ -537,40 +537,27 @@ virNetlinkNewLink(const char *ifname, if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0) goto buffer_too_small; - if (ifname && nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) < 0) - goto buffer_too_small; - - if (!(linkinfo = nla_nest_start(nl_msg, IFLA_LINKINFO))) - goto buffer_too_small; + NETLINK_MSG_PUT(nl_msg, IFLA_IFNAME, (strlen(ifname) + 1), ifname); - if (type && nla_put(nl_msg, IFLA_INFO_KIND, strlen(type)+1, type) < 0) - goto buffer_too_small; + NETLINK_MSG_NEST_START(nl_msg, linkinfo, IFLA_LINKINFO); + NETLINK_MSG_PUT(nl_msg, IFLA_INFO_KIND, (strlen(type) + 1), type); if ((STREQ(type, "macvtap") || STREQ(type, "macvlan")) && extra_args && extra_args->macvlan_mode && *extra_args->macvlan_mode > 0) { - if (!(infodata = nla_nest_start(nl_msg, IFLA_INFO_DATA))) - goto buffer_too_small; - - if (nla_put(nl_msg, IFLA_MACVLAN_MODE, sizeof(uint32_t), - extra_args->macvlan_mode) < 0) - goto buffer_too_small; - - nla_nest_end(nl_msg, infodata); + NETLINK_MSG_NEST_START(nl_msg, infodata, IFLA_INFO_DATA); + NETLINK_MSG_PUT(nl_msg, IFLA_MACVLAN_MODE, + sizeof(uint32_t), extra_args->macvlan_mode); + NETLINK_MSG_NEST_END(nl_msg, infodata); } - nla_nest_end(nl_msg, linkinfo); + NETLINK_MSG_NEST_END(nl_msg, linkinfo); if (extra_args) { - if (extra_args->ifindex && - nla_put(nl_msg, IFLA_LINK, sizeof(uint32_t), - extra_args->ifindex) < 0) - goto buffer_too_small; - - if (extra_args->mac && - nla_put(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, extra_args->mac) < 0) - goto buffer_too_small; + NETLINK_MSG_PUT(nl_msg, IFLA_LINK, sizeof(uint32_t), + extra_args->ifindex); + NETLINK_MSG_PUT(nl_msg, IFLA_ADDRESS, VIR_MAC_BUFLEN, extra_args->mac); } if (virNetlinkCommand(nl_msg, &resp, &buflen, 0, 0, NETLINK_ROUTE, 0) < 0) diff --git a/src/util/virnetlink.h b/src/util/virnetlink.h index 09bab08..fd140f0 100644 --- a/src/util/virnetlink.h +++ b/src/util/virnetlink.h @@ -48,6 +48,29 @@ struct nlmsghdr; # endif /* __linux__ */ +# define NETLINK_MSG_NEST_START(msg, container, attrtype) \ +do { \ + container = nla_nest_start(msg, attrtype); \ + if (!container) \ + goto buffer_too_small; \ +} while(0) + +# define NETLINK_MSG_NEST_END(msg, container) \ +do { nla_nest_end(msg, container); } while(0) + +/* + * we need to use an intermediary pointer to @data as compilers may sometimes + * complain about @data not being a pointer type: + * error: the address of 'foo' will always evaluate as 'true' [-Werror=address] + */ +# define NETLINK_MSG_PUT(msg, attrtype, datalen, data) \ +do { \ + const void *dataptr = data; \ + if (dataptr && nla_put(msg, attrtype, datalen, dataptr) < 0) \ + goto buffer_too_small; \ +} while(0) + + int virNetlinkStartup(void); void virNetlinkShutdown(void); -- 2.17.1