From 028c5aa18b5273c029f0278232d922ee1a164de6 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Wed, 22 May 2019 13:54:46 +0200 Subject: ip: use rtnl_send_check() on flush commands, closes 6962 function old new delta rtnl_send_check - 160 +160 xrtnl_wilddump_request 64 66 +2 ipneigh_list_or_flush 714 706 -8 rtnl_send 69 - -69 ------------------------------------------------------------------------------ (add/remove: 1/1 grow/shrink: 1/1 up/down: 162/-77) Total: 85 bytes Signed-off-by: Denys Vlasenko --- networking/libiproute/ipaddress.c | 6 ++++-- networking/libiproute/ipneigh.c | 9 ++++---- networking/libiproute/iproute.c | 5 ++++- networking/libiproute/libnetlink.c | 43 +++++++++++++++++++++++++++++++------- networking/libiproute/libnetlink.h | 19 +++++++++++++++-- 5 files changed, 65 insertions(+), 17 deletions(-) --- a/networking/libiproute/ipaddress.c +++ b/networking/libiproute/ipaddress.c @@ -23,6 +23,7 @@ struct filter_t { char *label; + /* Flush cmd buf. If !NULL, print_addrinfo() constructs flush commands in it */ char *flushb; struct rtnl_handle *rth; int scope, scopemask; @@ -34,6 +35,8 @@ struct filter_t { smallint showqueue; smallint oneline; smallint up; + /* Misnomer. Does not mean "flushed something" */ + /* More like "flush commands were constructed by print_addrinfo()" */ smallint flushed; inet_prefix pfx; } FIX_ALIASING; @@ -201,7 +204,7 @@ static NOINLINE int print_linkinfo(const static int flush_update(void) { - if (rtnl_send(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { + if (rtnl_send_check(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { bb_perror_msg("can't send flush request"); return -1; } @@ -507,7 +510,6 @@ int FAST_FUNC ipaddr_list_or_flush(char xrtnl_dump_filter(&rth, store_nlmsg, &ainfo); } - if (G_filter.family && G_filter.family != AF_PACKET) { struct nlmsg_list **lp; lp = &linfo; --- a/networking/libiproute/ipneigh.c +++ b/networking/libiproute/ipneigh.c @@ -32,7 +32,10 @@ struct filter_t { int state; int unused_only; inet_prefix pfx; + /* Misnomer. Does not mean "flushed N something" */ + /* More like "no_of_flush_commands_constructed_by_print_neigh()" */ int flushed; + /* Flush cmd buf. If !NULL, print_neigh() constructs flush commands in it */ char *flushb; int flushp; int flushe; @@ -45,7 +48,7 @@ typedef struct filter_t filter_t; static int flush_update(void) { - if (rtnl_send(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { + if (rtnl_send_check(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { bb_perror_msg("can't send flush request"); return -1; } @@ -299,9 +302,7 @@ static int FAST_FUNC ipneigh_list_or_flu G_filter.rth = &rth; while (round < MAX_ROUNDS) { - if (xrtnl_wilddump_request(&rth, G_filter.family, RTM_GETNEIGH) < 0) { - bb_perror_msg_and_die("can't send dump request"); - } + xrtnl_wilddump_request(&rth, G_filter.family, RTM_GETNEIGH); G_filter.flushed = 0; if (xrtnl_dump_filter(&rth, print_neigh, NULL) < 0) { bb_perror_msg_and_die("flush terminated"); --- a/networking/libiproute/iproute.c +++ b/networking/libiproute/iproute.c @@ -26,7 +26,10 @@ struct filter_t { int tb; + /* Misnomer. Does not mean "flushed something" */ + /* More like "flush commands were constructed by print_route()" */ smallint flushed; + /* Flush cmd buf. If !NULL, print_route() constructs flush commands in it */ char *flushb; int flushp; int flushe; @@ -53,7 +56,7 @@ typedef struct filter_t filter_t; static int flush_update(void) { - if (rtnl_send(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { + if (rtnl_send_check(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { bb_perror_msg("can't send flush request"); return -1; } --- a/networking/libiproute/libnetlink.c +++ b/networking/libiproute/libnetlink.c @@ -34,7 +34,7 @@ void FAST_FUNC xrtnl_open(struct rtnl_ha rth->seq = time(NULL); } -int FAST_FUNC xrtnl_wilddump_request(struct rtnl_handle *rth, int family, int type) +void FAST_FUNC xrtnl_wilddump_request(struct rtnl_handle *rth, int family, int type) { struct { struct nlmsghdr nlh; @@ -48,18 +48,45 @@ int FAST_FUNC xrtnl_wilddump_request(str req.nlh.nlmsg_seq = rth->dump = ++rth->seq; req.g.rtgen_family = family; - return rtnl_send(rth, (void*)&req, sizeof(req)); + rtnl_send(rth, (void*)&req, sizeof(req)); } -//TODO: pass rth->fd instead of full rth? -int FAST_FUNC rtnl_send(struct rtnl_handle *rth, char *buf, int len) +/* A version which checks for e.g. EPERM errors. + * Try: setuidgid 1:1 ip addr flush dev eth0 + */ +int FAST_FUNC rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len) { - struct sockaddr_nl nladdr; + struct nlmsghdr *h; + int status; + char resp[1024]; + + status = write(rth->fd, buf, len); + if (status < 0) + return status; + + /* Check for immediate errors */ + status = recv(rth->fd, resp, sizeof(resp), MSG_DONTWAIT|MSG_PEEK); + if (status < 0) { + if (errno == EAGAIN) /* if no error, this happens */ + return 0; + return -1; + } + + for (h = (struct nlmsghdr *)resp; + NLMSG_OK(h, status); + h = NLMSG_NEXT(h, status) + ) { + if (h->nlmsg_type == NLMSG_ERROR) { + struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h); + if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) + bb_error_msg("ERROR truncated"); + else + errno = -err->error; + return -1; + } + } - memset(&nladdr, 0, sizeof(nladdr)); - nladdr.nl_family = AF_NETLINK; - - return xsendto(rth->fd, buf, len, (struct sockaddr*)&nladdr, sizeof(nladdr)); + return 0; } int FAST_FUNC rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len) --- a/networking/libiproute/libnetlink.h +++ b/networking/libiproute/libnetlink.h @@ -20,7 +20,7 @@ struct rtnl_handle { extern void xrtnl_open(struct rtnl_handle *rth) FAST_FUNC; #define rtnl_close(rth) (close((rth)->fd)) -extern int xrtnl_wilddump_request(struct rtnl_handle *rth, int fam, int type) FAST_FUNC; +extern void xrtnl_wilddump_request(struct rtnl_handle *rth, int fam, int type) FAST_FUNC; extern int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len) FAST_FUNC; extern int xrtnl_dump_filter(struct rtnl_handle *rth, int (*filter)(const struct sockaddr_nl*, struct nlmsghdr *n, void*) FAST_FUNC, @@ -34,8 +34,23 @@ extern int rtnl_talk(struct rtnl_handle int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *), void *jarg) FAST_FUNC; -extern int rtnl_send(struct rtnl_handle *rth, char *buf, int) FAST_FUNC; +int rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len) FAST_FUNC; +//TODO: pass rth->fd instead of full rth? +static ALWAYS_INLINE void rtnl_send(struct rtnl_handle *rth, const void *buf, int len) +{ + // Used to be: + //struct sockaddr_nl nladdr; + //memset(&nladdr, 0, sizeof(nladdr)); + //nladdr.nl_family = AF_NETLINK; + //return xsendto(rth->fd, buf, len, (struct sockaddr*)&nladdr, sizeof(nladdr)); + // iproute2-4.2.0 simplified the above to: + //return send(rth->fd, buf, len, 0); + + // We are using even shorter: + xwrite(rth->fd, buf, len); + // and convert to void, inline. +} extern int addattr32(struct nlmsghdr *n, int maxlen, int type, uint32_t data) FAST_FUNC; extern int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen) FAST_FUNC;