Date: Tue, 9 Aug 2005 16:14:08 GMT From: Robert Watson <rwatson@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 81737 for review Message-ID: <200508091614.j79GE8it037432@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=81737 Change 81737 by rwatson@rwatson_peppercorn on 2005/08/09 16:13:47 Add helper function ip_findmoptions(), which accepts an inpcb, and attempts to atomically return either an existing set of IP multicast options for the PCB, or a newlly allocated set with default values. The inpcb is returned locked. This function may sleep. Call ip_moptions() to acquire a reference to a PCB's socket options, and perform the update of the options while holding the PCB lock. Release the lock before returning. Remove garbage collection of multicast options when values return to the default, as this complicates locking substantially. Most applications allocate a socket either to be multicast, or not, and don't tend to keep around sockets that have previously been used for multicast, then used for unicast. Affected files ... .. //depot/projects/netsmp/src/sys/netinet/ip_output.c#5 edit Differences ... ==== //depot/projects/netsmp/src/sys/netinet/ip_output.c#5 (text+ko) ==== @@ -99,6 +99,7 @@ static int ip_getmoptions(struct inpcb *, struct sockopt *); static int ip_pcbopts(struct inpcb *, int, struct mbuf *); static int ip_setmoptions(struct inpcb *, struct sockopt *); +static struct ip_moptions *ip_findmoptions(struct inpcb *inp); int ip_optcopy(struct ip *, struct ip *); @@ -1569,6 +1570,39 @@ } /* + * Given an inpcb, return its multicast options structure pointer. Accepts + * an unlocked inpcb pointer, but will return it locked. May sleep. + */ +static struct ip_moptions * +ip_findmoptions(struct inpcb *inp) +{ + struct ip_moptions *imo; + + INP_LOCK(inp); + if (inp->inp_moptions != NULL) + return (inp->inp_moptions); + + INP_UNLOCK(inp); + + imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS, M_WAITOK); + + imo->imo_multicast_ifp = NULL; + imo->imo_multicast_addr.s_addr = INADDR_ANY; + imo->imo_multicast_vif = -1; + imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL; + imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP; + imo->imo_num_memberships = 0; + + INP_LOCK(inp); + if (inp->inp_moptions != NULL) { + free(imo, M_IPMOPTS); + return (inp->inp_moptions); + } + inp->inp_moptions = imo; + return (imo); +} + +/* * Set the IP multicast options in response to user setsockopt(). */ static int @@ -1585,26 +1619,6 @@ int ifindex; int s; - imo = inp->inp_moptions; - if (imo == NULL) { - /* - * No multicast option buffer attached to the pcb; - * allocate one and initialize to default values. - */ - imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS, - M_WAITOK); - - if (imo == NULL) - return (ENOBUFS); - inp->inp_moptions = imo; - imo->imo_multicast_ifp = NULL; - imo->imo_multicast_addr.s_addr = INADDR_ANY; - imo->imo_multicast_vif = -1; - imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL; - imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP; - imo->imo_num_memberships = 0; - } - switch (sopt->sopt_name) { /* store an index number for the vif you wanna use in the send */ case IP_MULTICAST_VIF: @@ -1619,7 +1633,9 @@ error = EINVAL; break; } + imo = ip_findmoptions(inp); imo->imo_multicast_vif = i; + INP_UNLOCK(inp); break; case IP_MULTICAST_IF: @@ -1634,8 +1650,10 @@ * When no interface is selected, a default one is * chosen every time a multicast packet is sent. */ + imo = ip_findmoptions(inp); if (addr.s_addr == INADDR_ANY) { imo->imo_multicast_ifp = NULL; + INP_UNLOCK(inp); break; } /* @@ -1646,6 +1664,7 @@ s = splimp(); ifp = ip_multicast_if(&addr, &ifindex); if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) { + INP_UNLOCK(inp); splx(s); error = EADDRNOTAVAIL; break; @@ -1655,6 +1674,7 @@ imo->imo_multicast_addr = addr; else imo->imo_multicast_addr.s_addr = INADDR_ANY; + INP_UNLOCK(inp); splx(s); break; @@ -1670,7 +1690,9 @@ error = sooptcopyin(sopt, &ttl, 1, 1); if (error) break; + imo = ip_findmoptions(inp); imo->imo_multicast_ttl = ttl; + INP_UNLOCK(inp); } else { u_int ttl; error = sooptcopyin(sopt, &ttl, sizeof ttl, @@ -1679,8 +1701,11 @@ break; if (ttl > 255) error = EINVAL; - else + else { + imo = ip_findmoptions(inp); imo->imo_multicast_ttl = ttl; + INP_UNLOCK(inp); + } } break; @@ -1696,14 +1721,18 @@ error = sooptcopyin(sopt, &loop, 1, 1); if (error) break; + imo = ip_findmoptions(inp); imo->imo_multicast_loop = !!loop; + INP_UNLOCK(inp); } else { u_int loop; error = sooptcopyin(sopt, &loop, sizeof loop, sizeof loop); if (error) break; + imo = ip_findmoptions(inp); imo->imo_multicast_loop = !!loop; + INP_UNLOCK(inp); } break; @@ -1757,6 +1786,7 @@ * See if the membership already exists or if all the * membership slots are full. */ + imo = ip_findmoptions(inp); for (i = 0; i < imo->imo_num_memberships; ++i) { if (imo->imo_membership[i]->inm_ifp == ifp && imo->imo_membership[i]->inm_addr.s_addr @@ -1764,11 +1794,13 @@ break; } if (i < imo->imo_num_memberships) { + INP_UNLOCK(inp); error = EADDRINUSE; splx(s); break; } if (i == IP_MAX_MEMBERSHIPS) { + INP_UNLOCK(inp); error = ETOOMANYREFS; splx(s); break; @@ -1779,11 +1811,13 @@ */ if ((imo->imo_membership[i] = in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) { + INP_UNLOCK(inp); error = ENOBUFS; splx(s); break; } ++imo->imo_num_memberships; + INP_UNLOCK(inp); splx(s); break; @@ -1819,6 +1853,7 @@ /* * Find the membership in the membership array. */ + imo = ip_findmoptions(inp); for (i = 0; i < imo->imo_num_memberships; ++i) { if ((ifp == NULL || imo->imo_membership[i]->inm_ifp == ifp) && @@ -1827,6 +1862,7 @@ break; } if (i == imo->imo_num_memberships) { + INP_UNLOCK(inp); error = EADDRNOTAVAIL; splx(s); break; @@ -1842,6 +1878,7 @@ for (++i; i < imo->imo_num_memberships; ++i) imo->imo_membership[i-1] = imo->imo_membership[i]; --imo->imo_num_memberships; + INP_UNLOCK(inp); splx(s); break; @@ -1850,18 +1887,6 @@ break; } - /* - * If all options have default values, no need to keep the mbuf. - */ - if (imo->imo_multicast_ifp == NULL && - imo->imo_multicast_vif == -1 && - imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL && - imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP && - imo->imo_num_memberships == 0) { - free(inp->inp_moptions, M_IPMOPTS); - inp->inp_moptions = NULL; - } - return (error); }
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