From cce59ad7f117c058deebcb4ea093188e8b1b8434 Mon Sep 17 00:00:00 2001 From: Tim Kourt Date: Tue, 30 Jul 2019 18:16:11 -0700 Subject: [PATCH] rtnlutil: Add connected and gateway route API The API allows to add connected and gateway routes to the main routing table. rtnl_route_ipv4_add_gateway() is equivalent to the following example 'ip route' command: ip route add default via 10.0.0.1 dev wlan0 proto dhcp src 10.0.0.2 metric 339 rtnl_route_ipv4_add_connected() is equivalent to the following example 'ip route' command: sudo ip route add 10.0.0.0/24 dev wlan0 proto dhcp src 10.0.0.2 scope link The 'ip route' output from the above commands looks as follows: rtnl_route_ipv4_add_connected(): 10.0.0.0/24 dev wlan0 proto dhcp scope link src 10.0.0.2 rtnl_route_ipv4_add_gateway(): default via 10.0.0.1 dev wlan0 proto dhcp src 10.0.0.2 metric 339 --- src/rtnlutil.c | 124 +++++++++++++++++++++++++++++++++++++++++++++++++ src/rtnlutil.h | 13 ++++++ 2 files changed, 137 insertions(+) diff --git a/src/rtnlutil.c b/src/rtnlutil.c index 1e16ec5f..960e6ef1 100644 --- a/src/rtnlutil.c +++ b/src/rtnlutil.c @@ -43,6 +43,17 @@ static size_t rta_add_u8(void *rta_buf, unsigned short type, uint8_t value) return RTA_SPACE(sizeof(uint8_t)); } +static size_t rta_add_u32(void *rta_buf, unsigned short type, uint32_t value) +{ + struct rtattr *rta = rta_buf; + + rta->rta_len = RTA_LENGTH(sizeof(uint32_t)); + rta->rta_type = type; + *((uint32_t *) RTA_DATA(rta)) = value; + + return RTA_SPACE(sizeof(uint32_t)); +} + static size_t rta_add_data(void *rta_buf, unsigned short type, void *data, size_t data_len) { @@ -309,3 +320,116 @@ uint32_t rtnl_route_dump_ipv4(struct l_netlink *rtnl, sizeof(struct rtmsg), cb, user_data, destroy); } + +static uint32_t rtnl_route_add(struct l_netlink *rtnl, int ifindex, + uint8_t scope, uint8_t dst_len, + const char *dst, const char *gateway, + const char *src, + uint32_t priority_offset, uint8_t proto, + l_netlink_command_func_t cb, + void *user_data, + l_netlink_destroy_func_t destroy) +{ + struct rtmsg *rtmmsg; + struct in_addr in_addr; + size_t bufsize; + void *rta_buf; + uint32_t id; + uint16_t flags; + + if (!dst && !gateway) + return 0; + + bufsize = NLMSG_ALIGN(sizeof(struct rtmsg)) + + RTA_SPACE(sizeof(uint32_t)) + + (priority_offset ? RTA_SPACE(sizeof(uint32_t)) : 0) + + (gateway ? RTA_SPACE(sizeof(struct in_addr)) : 0) + + (src ? RTA_SPACE(sizeof(struct in_addr)) : 0) + + (dst ? RTA_SPACE(sizeof(struct in_addr)) : 0); + + rtmmsg = l_malloc(bufsize); + memset(rtmmsg, 0, bufsize); + + rtmmsg->rtm_family = AF_INET; + rtmmsg->rtm_table = RT_TABLE_MAIN; + rtmmsg->rtm_protocol = proto; + rtmmsg->rtm_type = RTN_UNICAST; + rtmmsg->rtm_scope = scope; + + flags = NLM_F_CREATE | NLM_F_REPLACE; + + + rta_buf = (void *) rtmmsg + NLMSG_ALIGN(sizeof(struct rtmsg)); + rta_buf += rta_add_u32(rta_buf, RTA_OIF, ifindex); + + if (priority_offset) + rta_buf += rta_add_u32(rta_buf, RTA_PRIORITY, + priority_offset + ifindex); + + if (dst) { + if (inet_pton(AF_INET, dst, &in_addr) < 1) { + l_free(rtmmsg); + + return 0; + } + + rtmmsg->rtm_dst_len = dst_len; + rta_buf += rta_add_data(rta_buf, RTA_DST, &in_addr, + sizeof(struct in_addr)); + } + + if (gateway) { + if (inet_pton(AF_INET, gateway, &in_addr) < 1) { + l_free(rtmmsg); + + return 0; + } + + rta_buf += rta_add_data(rta_buf, RTA_GATEWAY, &in_addr, + sizeof(struct in_addr)); + } + + if (src) { + if (inet_pton(AF_INET, src, &in_addr) < 1) { + l_free(rtmmsg); + + return 0; + } + + rtmmsg->rtm_src_len = 32; + rta_buf += rta_add_data(rta_buf, RTA_PREFSRC, &in_addr, + sizeof(struct in_addr)); + } + + id = l_netlink_send(rtnl, RTM_NEWROUTE, flags, rtmmsg, + rta_buf - (void *) rtmmsg, cb, user_data, + destroy); + + l_free(rtmmsg); + + return id; +} + +uint32_t rtnl_route_ipv4_add_connected(struct l_netlink *rtnl, int ifindex, + uint8_t dst_len, const char *dst, + const char *src, uint8_t proto, + l_netlink_command_func_t cb, + void *user_data, + l_netlink_destroy_func_t destroy) +{ + return rtnl_route_add(rtnl, ifindex, RT_SCOPE_LINK, dst_len, dst, NULL, + src, 0, proto, cb, user_data, destroy); +} + +uint32_t rtnl_route_ipv4_add_gateway(struct l_netlink *rtnl, int ifindex, + const char *gateway, const char *src, + uint32_t priority_offset, + uint8_t proto, + l_netlink_command_func_t cb, + void *user_data, + l_netlink_destroy_func_t destroy) +{ + return rtnl_route_add(rtnl, ifindex, RT_SCOPE_UNIVERSE, 0, NULL, + gateway, src, priority_offset, proto, cb, + user_data, destroy); +} diff --git a/src/rtnlutil.h b/src/rtnlutil.h index fc06160d..b159d959 100644 --- a/src/rtnlutil.h +++ b/src/rtnlutil.h @@ -54,3 +54,16 @@ void rtnl_route_extract_ipv4(const struct rtmsg *rtmsg, uint32_t len, uint32_t rtnl_route_dump_ipv4(struct l_netlink *rtnl, l_netlink_command_func_t cb, void *user_data, l_netlink_destroy_func_t destroy); +uint32_t rtnl_route_ipv4_add_connected(struct l_netlink *rtnl, int ifindex, + uint8_t dst_len, const char *dst, + const char *src, uint8_t proto, + l_netlink_command_func_t cb, + void *user_data, + l_netlink_destroy_func_t destroy); +uint32_t rtnl_route_ipv4_add_gateway(struct l_netlink *rtnl, int ifindex, + const char *gateway, const char *src, + uint32_t priority_offset, + uint8_t proto, + l_netlink_command_func_t cb, + void *user_data, + l_netlink_destroy_func_t destroy);