package/utils/busybox/patches/530-ip-use-rtnl_send_check-on-flush-commands.patch

   1 From 028c5aa18b5273c029f0278232d922ee1a164de6 Mon Sep 17 00:00:00 2001
   2 From: Denys Vlasenko <vda.linux@googlemail.com>
   3 Date: Wed, 22 May 2019 13:54:46 +0200
   4 Subject: ip: use rtnl_send_check() on flush commands, closes 6962
   5
   6 function                                             old     new   delta
   7 rtnl_send_check                                        -     160    +160
   8 xrtnl_wilddump_request                                64      66      +2
   9 ipneigh_list_or_flush                                714     706      -8
  10 rtnl_send                                             69       -     -69
  11 ------------------------------------------------------------------------------
  12 (add/remove: 1/1 grow/shrink: 1/1 up/down: 162/-77)            Total: 85 bytes
  13
  14 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
  15 ---
  16  networking/libiproute/ipaddress.c  |  6 ++++--
  17  networking/libiproute/ipneigh.c    |  9 ++++----
  18  networking/libiproute/iproute.c    |  5 ++++-
  19  networking/libiproute/libnetlink.c | 43 +++++++++++++++++++++++++++++++-------
  20  networking/libiproute/libnetlink.h | 19 +++++++++++++++--
  21  5 files changed, 65 insertions(+), 17 deletions(-)
  22
  23 --- a/networking/libiproute/ipaddress.c
  24 +++ b/networking/libiproute/ipaddress.c
  25 @@ -23,6 +23,7 @@
  26
  27  struct filter_t {
  28         char *label;
  29 +       /* Flush cmd buf. If !NULL, print_addrinfo() constructs flush commands in it */
  30         char *flushb;
  31         struct rtnl_handle *rth;
  32         int scope, scopemask;
  33 @@ -34,6 +35,8 @@ struct filter_t {
  34         smallint showqueue;
  35         smallint oneline;
  36         smallint up;
  37 +       /* Misnomer. Does not mean "flushed something" */
  38 +       /* More like "flush commands were constructed by print_addrinfo()" */
  39         smallint flushed;
  40         inet_prefix pfx;
  41  } FIX_ALIASING;
  42 @@ -201,7 +204,7 @@ static NOINLINE int print_linkinfo(const
  43
  44  static int flush_update(void)
  45  {
  46 -       if (rtnl_send(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) {
  47 +       if (rtnl_send_check(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) {
  48                 bb_perror_msg("can't send flush request");
  49                 return -1;
  50         }
  51 @@ -507,7 +510,6 @@ int FAST_FUNC ipaddr_list_or_flush(char
  52                 xrtnl_dump_filter(&rth, store_nlmsg, &ainfo);
  53         }
  54
  55 -
  56         if (G_filter.family && G_filter.family != AF_PACKET) {
  57                 struct nlmsg_list **lp;
  58                 lp = &linfo;
  59 --- a/networking/libiproute/ipneigh.c
  60 +++ b/networking/libiproute/ipneigh.c
  61 @@ -32,7 +32,10 @@ struct filter_t {
  62         int state;
  63         int unused_only;
  64         inet_prefix pfx;
  65 +       /* Misnomer. Does not mean "flushed N something" */
  66 +       /* More like "no_of_flush_commands_constructed_by_print_neigh()" */
  67         int flushed;
  68 +       /* Flush cmd buf. If !NULL, print_neigh() constructs flush commands in it */
  69         char *flushb;
  70         int flushp;
  71         int flushe;
  72 @@ -45,7 +48,7 @@ typedef struct filter_t filter_t;
  73
  74  static int flush_update(void)
  75  {
  76 -       if (rtnl_send(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) {
  77 +       if (rtnl_send_check(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) {
  78                 bb_perror_msg("can't send flush request");
  79                 return -1;
  80         }
  81 @@ -299,9 +302,7 @@ static int FAST_FUNC ipneigh_list_or_flu
  82                 G_filter.rth = &rth;
  83
  84                 while (round < MAX_ROUNDS) {
  85 -                       if (xrtnl_wilddump_request(&rth, G_filter.family, RTM_GETNEIGH) < 0) {
  86 -                               bb_perror_msg_and_die("can't send dump request");
  87 -                       }
  88 +                       xrtnl_wilddump_request(&rth, G_filter.family, RTM_GETNEIGH);
  89                         G_filter.flushed = 0;
  90                         if (xrtnl_dump_filter(&rth, print_neigh, NULL) < 0) {
  91                                 bb_perror_msg_and_die("flush terminated");
  92 --- a/networking/libiproute/iproute.c
  93 +++ b/networking/libiproute/iproute.c
  94 @@ -26,7 +26,10 @@
  95
  96  struct filter_t {
  97         int tb;
  98 +       /* Misnomer. Does not mean "flushed something" */
  99 +       /* More like "flush commands were constructed by print_route()" */
 100         smallint flushed;
 101 +       /* Flush cmd buf. If !NULL, print_route() constructs flush commands in it */
 102         char *flushb;
 103         int flushp;
 104         int flushe;
 105 @@ -53,7 +56,7 @@ typedef struct filter_t filter_t;
 106
 107  static int flush_update(void)
 108  {
 109 -       if (rtnl_send(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) {
 110 +       if (rtnl_send_check(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) {
 111                 bb_perror_msg("can't send flush request");
 112                 return -1;
 113         }
 114 --- a/networking/libiproute/libnetlink.c
 115 +++ b/networking/libiproute/libnetlink.c
 116 @@ -34,7 +34,7 @@ void FAST_FUNC xrtnl_open(struct rtnl_ha
 117         rth->seq = time(NULL);
 118  }
 119
 120 -int FAST_FUNC xrtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
 121 +void FAST_FUNC xrtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
 122  {
 123         struct {
 124                 struct nlmsghdr nlh;
 125 @@ -48,18 +48,45 @@ int FAST_FUNC xrtnl_wilddump_request(str
 126         req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
 127         req.g.rtgen_family = family;
 128
 129 -       return rtnl_send(rth, (void*)&req, sizeof(req));
 130 +       rtnl_send(rth, (void*)&req, sizeof(req));
 131  }
 132
 133 -//TODO: pass rth->fd instead of full rth?
 134 -int FAST_FUNC rtnl_send(struct rtnl_handle *rth, char *buf, int len)
 135 +/* A version which checks for e.g. EPERM errors.
 136 + * Try: setuidgid 1:1 ip addr flush dev eth0
 137 + */
 138 +int FAST_FUNC rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len)
 139  {
 140 -       struct sockaddr_nl nladdr;
 141 +       struct nlmsghdr *h;
 142 +       int status;
 143 +       char resp[1024];
 144 +
 145 +       status = write(rth->fd, buf, len);
 146 +       if (status < 0)
 147 +               return status;
 148 +
 149 +       /* Check for immediate errors */
 150 +       status = recv(rth->fd, resp, sizeof(resp), MSG_DONTWAIT|MSG_PEEK);
 151 +       if (status < 0) {
 152 +               if (errno == EAGAIN) /* if no error, this happens */
 153 +                       return 0;
 154 +               return -1;
 155 +       }
 156 +
 157 +       for (h = (struct nlmsghdr *)resp;
 158 +           NLMSG_OK(h, status);
 159 +           h = NLMSG_NEXT(h, status)
 160 +       ) {
 161 +               if (h->nlmsg_type == NLMSG_ERROR) {
 162 +                       struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
 163 +                       if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
 164 +                               bb_error_msg("ERROR truncated");
 165 +                       else
 166 +                               errno = -err->error;
 167 +                       return -1;
 168 +               }
 169 +       }
 170
 171 -       memset(&nladdr, 0, sizeof(nladdr));
 172 -       nladdr.nl_family = AF_NETLINK;
 173 -
 174 -       return xsendto(rth->fd, buf, len, (struct sockaddr*)&nladdr, sizeof(nladdr));
 175 +       return 0;
 176  }
 177
 178  int FAST_FUNC rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
 179 --- a/networking/libiproute/libnetlink.h
 180 +++ b/networking/libiproute/libnetlink.h
 181 @@ -20,7 +20,7 @@ struct rtnl_handle {
 182
 183  extern void xrtnl_open(struct rtnl_handle *rth) FAST_FUNC;
 184  #define rtnl_close(rth) (close((rth)->fd))
 185 -extern int xrtnl_wilddump_request(struct rtnl_handle *rth, int fam, int type) FAST_FUNC;
 186 +extern void xrtnl_wilddump_request(struct rtnl_handle *rth, int fam, int type) FAST_FUNC;
 187  extern int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len) FAST_FUNC;
 188  extern int xrtnl_dump_filter(struct rtnl_handle *rth,
 189                 int (*filter)(const struct sockaddr_nl*, struct nlmsghdr *n, void*) FAST_FUNC,
 190 @@ -34,8 +34,23 @@ extern int rtnl_talk(struct rtnl_handle
 191                 int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
 192                 void *jarg) FAST_FUNC;
 193
 194 -extern int rtnl_send(struct rtnl_handle *rth, char *buf, int) FAST_FUNC;
 195 +int rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len) FAST_FUNC;
 196 +//TODO: pass rth->fd instead of full rth?
 197 +static ALWAYS_INLINE void rtnl_send(struct rtnl_handle *rth, const void *buf, int len)
 198 +{
 199 +       // Used to be:
 200 +       //struct sockaddr_nl nladdr;
 201 +       //memset(&nladdr, 0, sizeof(nladdr));
 202 +       //nladdr.nl_family = AF_NETLINK;
 203 +       //return xsendto(rth->fd, buf, len, (struct sockaddr*)&nladdr, sizeof(nladdr));
 204
 205 +       // iproute2-4.2.0 simplified the above to:
 206 +       //return send(rth->fd, buf, len, 0);
 207 +
 208 +       // We are using even shorter:
 209 +       xwrite(rth->fd, buf, len);
 210 +       // and convert to void, inline.
 211 +}
 212
 213  extern int addattr32(struct nlmsghdr *n, int maxlen, int type, uint32_t data) FAST_FUNC;
 214  extern int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen) FAST_FUNC;