Improve memory allocation model for rt_msg2() rtsock messages:
* memory is now allocated as early as possible, without holding locks. * sysctl users are now guaranteed to get a response (M_WAITOK buffer prealloc). * socket users are more likely to use on-stack buffer for replies. * standard kernel malloc/free functions are now used instead of radix wrappers. rt_msg2() has been renamed to rtsock_msg_buffer(). MFC after: 1 month
This commit is contained in:
Alexander V. Chernikov
parent
73e46dba11
commit
f2e5eb368a
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=265019
160
sys/net/rtsock.c
160
sys/net/rtsock.c
@ -152,8 +152,8 @@ struct walkarg {
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static void rts_input(struct mbuf *m);
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static struct mbuf *rt_msg1(int type, struct rt_addrinfo *rtinfo);
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static int rt_msg2(int type, struct rt_addrinfo *rtinfo,
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caddr_t cp, struct walkarg *w);
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static int rtsock_msg_buffer(int type, struct rt_addrinfo *rtinfo,
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struct walkarg *w, int *plen);
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static int rt_xaddrs(caddr_t cp, caddr_t cplim,
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struct rt_addrinfo *rtinfo);
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static int sysctl_dumpentry(struct radix_node *rn, void *vw);
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@ -526,11 +526,13 @@ route_output(struct mbuf *m, struct socket *so)
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struct sockaddr_in6 *sin6;
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int i, rti_need_deembed = 0;
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#endif
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int len, error = 0, fibnum;
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int alloc_len = 0, len, error = 0, fibnum;
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struct ifnet *ifp = NULL;
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union sockaddr_union saun;
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sa_family_t saf = AF_UNSPEC;
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struct rawcb *rp = NULL;
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struct walkarg w;
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char msgbuf[512];
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fibnum = so->so_fibnum;
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@ -545,15 +547,31 @@ route_output(struct mbuf *m, struct socket *so)
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len != mtod(m, struct rt_msghdr *)->rtm_msglen)
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senderr(EINVAL);
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R_Malloc(rtm, struct rt_msghdr *, len);
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if (rtm == NULL)
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senderr(ENOBUFS);
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/*
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* Most of current messages are in range 200-240 bytes,
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* minimize possible failures by using on-stack buffer
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* which should fit for most messages.
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* However, use stable memory if we need to handle
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* something large.
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*/
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if (len < sizeof(msgbuf)) {
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alloc_len = sizeof(msgbuf);
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rtm = (struct rt_msghdr *)msgbuf;
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} else {
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alloc_len = roundup2(len, 1024);
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rtm = malloc(alloc_len, M_TEMP, M_NOWAIT);
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if (rtm == NULL)
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senderr(ENOBUFS);
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}
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m_copydata(m, 0, len, (caddr_t)rtm);
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bzero(&info, sizeof(info));
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bzero(&w, sizeof(w));
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if (rtm->rtm_version != RTM_VERSION) {
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/* Do not touch message since format is unknown */
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Free(rtm);
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if ((char *)rtm != msgbuf)
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free(rtm, M_TEMP);
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rtm = NULL;
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senderr(EPROTONOSUPPORT);
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}
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@ -798,18 +816,26 @@ route_output(struct mbuf *m, struct socket *so)
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} else if ((ifp = rt->rt_ifp) != NULL) {
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rtm->rtm_index = ifp->if_index;
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}
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len = rt_msg2(rtm->rtm_type, &info, NULL, NULL);
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if (len > rtm->rtm_msglen) {
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/* Check if we need to realloc storage */
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rtsock_msg_buffer(rtm->rtm_type, &info, NULL, &len);
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if (len > alloc_len) {
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struct rt_msghdr *new_rtm;
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R_Malloc(new_rtm, struct rt_msghdr *, len);
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new_rtm = malloc(len, M_TEMP, M_NOWAIT);
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if (new_rtm == NULL) {
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RT_UNLOCK(rt);
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senderr(ENOBUFS);
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}
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bcopy(rtm, new_rtm, rtm->rtm_msglen);
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Free(rtm); rtm = new_rtm;
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free(rtm, M_TEMP);
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rtm = new_rtm;
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alloc_len = len;
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}
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(void)rt_msg2(rtm->rtm_type, &info, (caddr_t)rtm, NULL);
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w.w_tmem = (caddr_t)rtm;
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w.w_tmemsize = alloc_len;
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rtsock_msg_buffer(rtm->rtm_type, &info, &w, &len);
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if (rt->rt_flags & RTF_GWFLAG_COMPAT)
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rtm->rtm_flags = RTF_GATEWAY |
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(rt->rt_flags & ~RTF_GWFLAG_COMPAT);
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@ -833,8 +859,8 @@ route_output(struct mbuf *m, struct socket *so)
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*/
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if ((so->so_options & SO_USELOOPBACK) == 0) {
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if (V_route_cb.any_count <= 1) {
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if (rtm != NULL)
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Free(rtm);
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if (rtm != NULL && (char *)rtm != msgbuf)
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free(rtm, M_TEMP);
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m_freem(m);
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return (error);
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}
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@ -870,7 +896,9 @@ route_output(struct mbuf *m, struct socket *so)
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m = NULL;
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} else if (m->m_pkthdr.len > rtm->rtm_msglen)
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m_adj(m, rtm->rtm_msglen - m->m_pkthdr.len);
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Free(rtm);
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if ((char *)rtm != msgbuf)
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free(rtm, M_TEMP);
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}
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if (m != NULL) {
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M_SETFIB(m, fibnum);
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@ -1041,21 +1069,26 @@ rt_msg1(int type, struct rt_addrinfo *rtinfo)
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}
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/*
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* Used by the sysctl code and routing socket.
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* Writes information related to @rtinfo object to preallocated buffer.
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* Stores needed size in @plen. If @w is NULL, calculates size without
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* writing.
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* Used for sysctl dumps and rtsock answers (RTM_DEL/RTM_GET) generation.
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*
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* Returns 0 on success.
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*
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*/
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static int
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rt_msg2(int type, struct rt_addrinfo *rtinfo, caddr_t cp, struct walkarg *w)
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rtsock_msg_buffer(int type, struct rt_addrinfo *rtinfo, struct walkarg *w, int *plen)
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{
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int i;
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int len, dlen, second_time = 0;
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caddr_t cp0;
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int len, buflen = 0, dlen;
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caddr_t cp;
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struct rt_msghdr *rtm = NULL;
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#ifdef INET6
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struct sockaddr_storage ss;
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struct sockaddr_in6 *sin6;
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#endif
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rtinfo->rti_addrs = 0;
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again:
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switch (type) {
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case RTM_DELADDR:
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@ -1094,9 +1127,14 @@ rt_msg2(int type, struct rt_addrinfo *rtinfo, caddr_t cp, struct walkarg *w)
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default:
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len = sizeof(struct rt_msghdr);
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}
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cp0 = cp;
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if (cp0)
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cp += len;
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if (w != NULL) {
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rtm = (struct rt_msghdr *)w->w_tmem;
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buflen = w->w_tmemsize - len;
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cp = (caddr_t)w->w_tmem + len;
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}
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rtinfo->rti_addrs = 0;
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for (i = 0; i < RTAX_MAX; i++) {
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struct sockaddr *sa;
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@ -1104,7 +1142,7 @@ rt_msg2(int type, struct rt_addrinfo *rtinfo, caddr_t cp, struct walkarg *w)
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continue;
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rtinfo->rti_addrs |= (1 << i);
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dlen = SA_SIZE(sa);
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if (cp) {
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if (cp != NULL && buflen >= dlen) {
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#ifdef INET6
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if (V_deembed_scopeid && sa->sa_family == AF_INET6) {
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sin6 = (struct sockaddr_in6 *)&ss;
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@ -1115,37 +1153,40 @@ rt_msg2(int type, struct rt_addrinfo *rtinfo, caddr_t cp, struct walkarg *w)
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#endif
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bcopy((caddr_t)sa, cp, (unsigned)dlen);
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cp += dlen;
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buflen -= dlen;
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} else if (cp != NULL) {
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/*
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* Buffer too small. Count needed size
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* and return with error.
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*/
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cp = NULL;
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}
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len += dlen;
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}
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len = ALIGN(len);
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if (cp == NULL && w != NULL && !second_time) {
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struct walkarg *rw = w;
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if (rw->w_req) {
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if (rw->w_tmemsize < len) {
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if (rw->w_tmem)
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free(rw->w_tmem, M_RTABLE);
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rw->w_tmem = (caddr_t)
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malloc(len, M_RTABLE, M_NOWAIT);
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if (rw->w_tmem)
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rw->w_tmemsize = len;
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}
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if (rw->w_tmem) {
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cp = rw->w_tmem;
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second_time = 1;
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goto again;
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}
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}
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if (cp != NULL) {
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dlen = ALIGN(len) - len;
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if (buflen < dlen)
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cp = NULL;
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else
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buflen -= dlen;
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}
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if (cp) {
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struct rt_msghdr *rtm = (struct rt_msghdr *)cp0;
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len = ALIGN(len);
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if (cp != NULL) {
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/* fill header iff buffer is large enough */
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rtm->rtm_version = RTM_VERSION;
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rtm->rtm_type = type;
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rtm->rtm_msglen = len;
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}
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return (len);
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*plen = len;
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if (w != NULL && cp == NULL)
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return (ENOBUFS);
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return (0);
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}
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/*
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@ -1473,7 +1514,8 @@ sysctl_dumpentry(struct radix_node *rn, void *vw)
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if (rt->rt_ifp->if_flags & IFF_POINTOPOINT)
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info.rti_info[RTAX_BRD] = rt->rt_ifa->ifa_dstaddr;
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}
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size = rt_msg2(RTM_GET, &info, NULL, w);
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if ((error = rtsock_msg_buffer(RTM_GET, &info, w, &size)) != 0)
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return (error);
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if (w->w_req && w->w_tmem) {
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struct rt_msghdr *rtm = (struct rt_msghdr *)w->w_tmem;
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@ -1649,7 +1691,9 @@ sysctl_iflist(int af, struct walkarg *w)
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IF_ADDR_RLOCK(ifp);
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ifa = ifp->if_addr;
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info.rti_info[RTAX_IFP] = ifa->ifa_addr;
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len = rt_msg2(RTM_IFINFO, &info, NULL, w);
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error = rtsock_msg_buffer(RTM_IFINFO, &info, w, &len);
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if (error != 0)
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goto done;
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info.rti_info[RTAX_IFP] = NULL;
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if (w->w_req && w->w_tmem) {
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if (w->w_op == NET_RT_IFLISTL)
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@ -1668,7 +1712,9 @@ sysctl_iflist(int af, struct walkarg *w)
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info.rti_info[RTAX_IFA] = ifa->ifa_addr;
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info.rti_info[RTAX_NETMASK] = ifa->ifa_netmask;
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info.rti_info[RTAX_BRD] = ifa->ifa_dstaddr;
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len = rt_msg2(RTM_NEWADDR, &info, NULL, w);
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error = rtsock_msg_buffer(RTM_NEWADDR, &info, w, &len);
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if (error != 0)
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goto done;
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if (w->w_req && w->w_tmem) {
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if (w->w_op == NET_RT_IFLISTL)
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error = sysctl_iflist_ifaml(ifa, &info,
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@ -1718,7 +1764,9 @@ sysctl_ifmalist(int af, struct walkarg *w)
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info.rti_info[RTAX_GATEWAY] =
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(ifma->ifma_addr->sa_family != AF_LINK) ?
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ifma->ifma_lladdr : NULL;
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len = rt_msg2(RTM_NEWMADDR, &info, NULL, w);
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error = rtsock_msg_buffer(RTM_NEWADDR, &info, w, &len);
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if (error != 0)
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goto done;
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if (w->w_req && w->w_tmem) {
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struct ifma_msghdr *ifmam;
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@ -1778,6 +1826,14 @@ sysctl_rtsock(SYSCTL_HANDLER_ARGS)
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error = sysctl_wire_old_buffer(req, 0);
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if (error)
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return (error);
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/*
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* Allocate reply buffer in advance.
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* All rtsock messages has maximum length of u_short.
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*/
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w.w_tmemsize = 65536;
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w.w_tmem = malloc(w.w_tmemsize, M_TEMP, M_WAITOK);
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switch (w.w_op) {
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case NET_RT_DUMP:
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@ -1824,8 +1880,8 @@ sysctl_rtsock(SYSCTL_HANDLER_ARGS)
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error = sysctl_ifmalist(af, &w);
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break;
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}
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if (w.w_tmem)
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free(w.w_tmem, M_RTABLE);
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free(w.w_tmem, M_TEMP);
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return (error);
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}
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