Author: melifaro
Date: Sun Apr 27 17:41:18 2014
New Revision: 265019
URL: http://svnweb.freebsd.org/changeset/base/265019
Log:
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
Modified:
head/sys/net/rtsock.c
Modified: head/sys/net/rtsock.c
==============================================================================
--- head/sys/net/rtsock.c Sun Apr 27 16:40:40 2014 (r265018)
+++ head/sys/net/rtsock.c Sun Apr 27 17:41:18 2014 (r265019)
@@ -152,8 +152,8 @@ struct walkarg {
static void rts_input(struct mbuf *m);
static struct mbuf *rt_msg1(int type, struct rt_addrinfo *rtinfo);
-static int rt_msg2(int type, struct rt_addrinfo *rtinfo,
- caddr_t cp, struct walkarg *w);
+static int rtsock_msg_buffer(int type, struct rt_addrinfo *rtinfo,
+ struct walkarg *w, int *plen);
static int rt_xaddrs(caddr_t cp, caddr_t cplim,
struct rt_addrinfo *rtinfo);
static int sysctl_dumpentry(struct radix_node *rn, void *vw);
@@ -526,11 +526,13 @@ route_output(struct mbuf *m, struct sock
struct sockaddr_in6 *sin6;
int i, rti_need_deembed = 0;
#endif
- int len, error = 0, fibnum;
+ int alloc_len = 0, len, error = 0, fibnum;
struct ifnet *ifp = NULL;
union sockaddr_union saun;
sa_family_t saf = AF_UNSPEC;
struct rawcb *rp = NULL;
+ struct walkarg w;
+ char msgbuf[512];
fibnum = so->so_fibnum;
@@ -545,15 +547,31 @@ route_output(struct mbuf *m, struct sock
len != mtod(m, struct rt_msghdr *)->rtm_msglen)
senderr(EINVAL);
- R_Malloc(rtm, struct rt_msghdr *, len);
- if (rtm == NULL)
- senderr(ENOBUFS);
+ /*
+ * Most of current messages are in range 200-240 bytes,
+ * minimize possible failures by using on-stack buffer
+ * which should fit for most messages.
+ * However, use stable memory if we need to handle
+ * something large.
+ */
+ if (len < sizeof(msgbuf)) {
+ alloc_len = sizeof(msgbuf);
+ rtm = (struct rt_msghdr *)msgbuf;
+ } else {
+ alloc_len = roundup2(len, 1024);
+ rtm = malloc(alloc_len, M_TEMP, M_NOWAIT);
+ if (rtm == NULL)
+ senderr(ENOBUFS);
+ }
+
m_copydata(m, 0, len, (caddr_t)rtm);
bzero(&info, sizeof(info));
+ bzero(&w, sizeof(w));
if (rtm->rtm_version != RTM_VERSION) {
/* Do not touch message since format is unknown */
- Free(rtm);
+ if ((char *)rtm != msgbuf)
+ free(rtm, M_TEMP);
rtm = NULL;
senderr(EPROTONOSUPPORT);
}
@@ -798,18 +816,26 @@ report:
} else if ((ifp = rt->rt_ifp) != NULL) {
rtm->rtm_index = ifp->if_index;
}
- len = rt_msg2(rtm->rtm_type, &info, NULL, NULL);
- if (len > rtm->rtm_msglen) {
+
+ /* Check if we need to realloc storage */
+ rtsock_msg_buffer(rtm->rtm_type, &info, NULL, &len);
+ if (len > alloc_len) {
struct rt_msghdr *new_rtm;
- R_Malloc(new_rtm, struct rt_msghdr *, len);
+ new_rtm = malloc(len, M_TEMP, M_NOWAIT);
if (new_rtm == NULL) {
RT_UNLOCK(rt);
senderr(ENOBUFS);
}
bcopy(rtm, new_rtm, rtm->rtm_msglen);
- Free(rtm); rtm = new_rtm;
+ free(rtm, M_TEMP);
+ rtm = new_rtm;
+ alloc_len = len;
}
- (void)rt_msg2(rtm->rtm_type, &info, (caddr_t)rtm, NULL);
+
+ w.w_tmem = (caddr_t)rtm;
+ w.w_tmemsize = alloc_len;
+ rtsock_msg_buffer(rtm->rtm_type, &info, &w, &len);
+
if (rt->rt_flags & RTF_GWFLAG_COMPAT)
rtm->rtm_flags = RTF_GATEWAY |
(rt->rt_flags & ~RTF_GWFLAG_COMPAT);
@@ -833,8 +859,8 @@ flush:
*/
if ((so->so_options & SO_USELOOPBACK) == 0) {
if (V_route_cb.any_count <= 1) {
- if (rtm != NULL)
- Free(rtm);
+ if (rtm != NULL && (char *)rtm != msgbuf)
+ free(rtm, M_TEMP);
m_freem(m);
return (error);
}
@@ -870,7 +896,9 @@ flush:
m = NULL;
} else if (m->m_pkthdr.len > rtm->rtm_msglen)
m_adj(m, rtm->rtm_msglen - m->m_pkthdr.len);
- Free(rtm);
+
+ if ((char *)rtm != msgbuf)
+ free(rtm, M_TEMP);
}
if (m != NULL) {
M_SETFIB(m, fibnum);
@@ -1041,21 +1069,26 @@ rt_msg1(int type, struct rt_addrinfo *rt
}
/*
- * Used by the sysctl code and routing socket.
+ * Writes information related to @rtinfo object to preallocated buffer.
+ * Stores needed size in @plen. If @w is NULL, calculates size without
+ * writing.
+ * Used for sysctl dumps and rtsock answers (RTM_DEL/RTM_GET) generation.
+ *
+ * Returns 0 on success.
+ *
*/
static int
-rt_msg2(int type, struct rt_addrinfo *rtinfo, caddr_t cp, struct walkarg *w)
+rtsock_msg_buffer(int type, struct rt_addrinfo *rtinfo, struct walkarg *w, int
*plen)
{
int i;
- int len, dlen, second_time = 0;
- caddr_t cp0;
+ int len, buflen = 0, dlen;
+ caddr_t cp;
+ struct rt_msghdr *rtm = NULL;
#ifdef INET6
struct sockaddr_storage ss;
struct sockaddr_in6 *sin6;
#endif
- rtinfo->rti_addrs = 0;
-again:
switch (type) {
case RTM_DELADDR:
@@ -1094,9 +1127,14 @@ again:
default:
len = sizeof(struct rt_msghdr);
}
- cp0 = cp;
- if (cp0)
- cp += len;
+
+ if (w != NULL) {
+ rtm = (struct rt_msghdr *)w->w_tmem;
+ buflen = w->w_tmemsize - len;
+ cp = (caddr_t)w->w_tmem + len;
+ }
+
+ rtinfo->rti_addrs = 0;
for (i = 0; i < RTAX_MAX; i++) {
struct sockaddr *sa;
@@ -1104,7 +1142,7 @@ again:
continue;
rtinfo->rti_addrs |= (1 << i);
dlen = SA_SIZE(sa);
- if (cp) {
+ if (cp != NULL && buflen >= dlen) {
#ifdef INET6
if (V_deembed_scopeid && sa->sa_family == AF_INET6) {
sin6 = (struct sockaddr_in6 *)&ss;
@@ -1115,37 +1153,40 @@ again:
#endif
bcopy((caddr_t)sa, cp, (unsigned)dlen);
cp += dlen;
+ buflen -= dlen;
+ } else if (cp != NULL) {
+ /*
+ * Buffer too small. Count needed size
+ * and return with error.
+ */
+ cp = NULL;
}
+
len += dlen;
}
- len = ALIGN(len);
- if (cp == NULL && w != NULL && !second_time) {
- struct walkarg *rw = w;
- if (rw->w_req) {
- if (rw->w_tmemsize < len) {
- if (rw->w_tmem)
- free(rw->w_tmem, M_RTABLE);
- rw->w_tmem = (caddr_t)
- malloc(len, M_RTABLE, M_NOWAIT);
- if (rw->w_tmem)
- rw->w_tmemsize = len;
- }
- if (rw->w_tmem) {
- cp = rw->w_tmem;
- second_time = 1;
- goto again;
- }
- }
+ if (cp != NULL) {
+ dlen = ALIGN(len) - len;
+ if (buflen < dlen)
+ cp = NULL;
+ else
+ buflen -= dlen;
}
- if (cp) {
- struct rt_msghdr *rtm = (struct rt_msghdr *)cp0;
+ len = ALIGN(len);
+ if (cp != NULL) {
+ /* fill header iff buffer is large enough */
rtm->rtm_version = RTM_VERSION;
rtm->rtm_type = type;
rtm->rtm_msglen = len;
}
- return (len);
+
+ *plen = len;
+
+ if (w != NULL && cp == NULL)
+ return (ENOBUFS);
+
+ return (0);
}
/*
@@ -1473,7 +1514,8 @@ sysctl_dumpentry(struct radix_node *rn,
if (rt->rt_ifp->if_flags & IFF_POINTOPOINT)
info.rti_info[RTAX_BRD] = rt->rt_ifa->ifa_dstaddr;
}
- size = rt_msg2(RTM_GET, &info, NULL, w);
+ if ((error = rtsock_msg_buffer(RTM_GET, &info, w, &size)) != 0)
+ return (error);
if (w->w_req && w->w_tmem) {
struct rt_msghdr *rtm = (struct rt_msghdr *)w->w_tmem;
@@ -1649,7 +1691,9 @@ sysctl_iflist(int af, struct walkarg *w)
IF_ADDR_RLOCK(ifp);
ifa = ifp->if_addr;
info.rti_info[RTAX_IFP] = ifa->ifa_addr;
- len = rt_msg2(RTM_IFINFO, &info, NULL, w);
+ error = rtsock_msg_buffer(RTM_IFINFO, &info, w, &len);
+ if (error != 0)
+ goto done;
info.rti_info[RTAX_IFP] = NULL;
if (w->w_req && w->w_tmem) {
if (w->w_op == NET_RT_IFLISTL)
@@ -1668,7 +1712,9 @@ sysctl_iflist(int af, struct walkarg *w)
info.rti_info[RTAX_IFA] = ifa->ifa_addr;
info.rti_info[RTAX_NETMASK] = ifa->ifa_netmask;
info.rti_info[RTAX_BRD] = ifa->ifa_dstaddr;
- len = rt_msg2(RTM_NEWADDR, &info, NULL, w);
+ error = rtsock_msg_buffer(RTM_NEWADDR, &info, w, &len);
+ if (error != 0)
+ goto done;
if (w->w_req && w->w_tmem) {
if (w->w_op == NET_RT_IFLISTL)
error = sysctl_iflist_ifaml(ifa, &info,
@@ -1718,7 +1764,9 @@ sysctl_ifmalist(int af, struct walkarg *
info.rti_info[RTAX_GATEWAY] =
(ifma->ifma_addr->sa_family != AF_LINK) ?
ifma->ifma_lladdr : NULL;
- len = rt_msg2(RTM_NEWMADDR, &info, NULL, w);
+ error = rtsock_msg_buffer(RTM_NEWADDR, &info, w, &len);
+ if (error != 0)
+ goto done;
if (w->w_req && w->w_tmem) {
struct ifma_msghdr *ifmam;
@@ -1778,6 +1826,14 @@ sysctl_rtsock(SYSCTL_HANDLER_ARGS)
error = sysctl_wire_old_buffer(req, 0);
if (error)
return (error);
+
+ /*
+ * Allocate reply buffer in advance.
+ * All rtsock messages has maximum length of u_short.
+ */
+ w.w_tmemsize = 65536;
+ w.w_tmem = malloc(w.w_tmemsize, M_TEMP, M_WAITOK);
+
switch (w.w_op) {
case NET_RT_DUMP:
@@ -1824,8 +1880,8 @@ sysctl_rtsock(SYSCTL_HANDLER_ARGS)
error = sysctl_ifmalist(af, &w);
break;
}
- if (w.w_tmem)
- free(w.w_tmem, M_RTABLE);
+
+ free(w.w_tmem, M_TEMP);
return (error);
}
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