The branch main has been updated by donner: URL: https://cgit.FreeBSD.org/src/commit/?id=9efcad61d8309ecad3c15392b277fd329a1e45e4
commit 9efcad61d8309ecad3c15392b277fd329a1e45e4 Author: Lutz Donnerhacke <[email protected]> AuthorDate: 2021-05-28 17:17:40 +0000 Commit: Lutz Donnerhacke <[email protected]> CommitDate: 2021-06-19 19:40:09 +0000 libalias: Restructure - Use AliasRange instead of PORT_BASE Get rid of PORT_BASE, replace by AliasRange. Simplify code. Factor out the search for a new port. Improves the perfomance a bit. Discussed with: Dimitry Luhtionov MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D30581 --- sys/netinet/libalias/alias_db.c | 171 +++++++++++++++++----------------------- 1 file changed, 74 insertions(+), 97 deletions(-) diff --git a/sys/netinet/libalias/alias_db.c b/sys/netinet/libalias/alias_db.c index 5f199394eb99..6bfe19a9b2a9 100644 --- a/sys/netinet/libalias/alias_db.c +++ b/sys/netinet/libalias/alias_db.c @@ -574,12 +574,20 @@ FindLinkOut(struct libalias *, struct in_addr, struct in_addr, u_short, u_short, static struct alias_link * FindLinkIn(struct libalias *, struct in_addr, struct in_addr, u_short, u_short, int, int); -#define ALIAS_PORT_BASE 0x08000 -#define ALIAS_PORT_MASK 0x07fff -#define ALIAS_PORT_MASK_EVEN 0x07ffe +static u_short _RandomPort(struct libalias *la); + #define GET_NEW_PORT_MAX_ATTEMPTS 20 -#define FIND_EVEN_ALIAS_BASE 1 +/* get random port in network byte order */ +static u_short +_RandomPort(struct libalias *la) { + u_short port; + + port = la->aliasPortLower + + arc4random_uniform(la->aliasPortLength); + + return ntohs(port); +} /* GetNewPort() allocates port numbers. Note that if a port number is already in use, that does not mean that it cannot be used by @@ -591,8 +599,7 @@ GetNewPort(struct libalias *la, struct alias_link *lnk, int alias_port_param) { int i; int max_trials; - u_short port_sys; - u_short port_net; + u_short port; LIBALIAS_LOCK_ASSERT(la); /* @@ -600,41 +607,18 @@ GetNewPort(struct libalias *la, struct alias_link *lnk, int alias_port_param) * this parameter is zero or positive, it precisely specifies * the port number. GetNewPort() will return this number * without check that it is in use. - + * + * The aliasing port is automatically selected by one of + * two methods below: + * * When this parameter is GET_ALIAS_PORT, it indicates to get * a randomly selected port number. */ - if (alias_port_param == GET_ALIAS_PORT) { - /* - * The aliasing port is automatically selected by one of - * two methods below: - */ - max_trials = GET_NEW_PORT_MAX_ATTEMPTS; - - if (la->packetAliasMode & PKT_ALIAS_SAME_PORTS) { - /* - * When the PKT_ALIAS_SAME_PORTS option is chosen, - * the first try will be the actual source port. If - * this is already in use, the remainder of the - * trials will be random. - */ - port_net = lnk->src_port; - port_sys = ntohs(port_net); - } else if (la->aliasPortLower) { - /* First trial is a random port in the aliasing range. */ - port_sys = la->aliasPortLower + - (arc4random() % la->aliasPortLength); - port_net = htons(port_sys); - } else { - /* First trial and all subsequent are random. */ - port_sys = arc4random() & ALIAS_PORT_MASK; - port_sys += ALIAS_PORT_BASE; - port_net = htons(port_sys); - } - } else if (alias_port_param >= 0 && alias_port_param < 0x10000) { + if (alias_port_param >= 0 && alias_port_param < 0x10000) { lnk->alias_port = (u_short) alias_port_param; return (0); - } else { + } + if (alias_port_param != GET_ALIAS_PORT) { #ifdef LIBALIAS_DEBUG fprintf(stderr, "PacketAlias/GetNewPort(): "); fprintf(stderr, "input parameter error\n"); @@ -642,58 +626,57 @@ GetNewPort(struct libalias *la, struct alias_link *lnk, int alias_port_param) return (-1); } + max_trials = GET_NEW_PORT_MAX_ATTEMPTS; + + /* + * When the PKT_ALIAS_SAME_PORTS option is chosen, + * the first try will be the actual source port. If + * this is already in use, the remainder of the + * trials will be random. + */ + port = (la->packetAliasMode & PKT_ALIAS_SAME_PORTS) + ? lnk->src_port + : _RandomPort(la); + /* Port number search */ - for (i = 0; i < max_trials; i++) { - int go_ahead; + for (i = 0; i < max_trials; i++, port = _RandomPort(la)) { + struct group_in *grp; struct alias_link *search_result; - search_result = FindLinkIn(la, lnk->dst_addr, lnk->alias_addr, - lnk->dst_port, port_net, - lnk->link_type, 0); + grp = StartPointIn(la, lnk->alias_addr, port, lnk->link_type, 0); + if (grp == NULL) + break; + LIST_FOREACH(search_result, &grp->full, all.in) { + if (lnk->dst_addr.s_addr == search_result->dst_addr.s_addr && + lnk->dst_port == search_result->dst_port) + break; /* found match */ + } if (search_result == NULL) - go_ahead = 1; - else if (!(lnk->flags & LINK_PARTIALLY_SPECIFIED) - && (search_result->flags & LINK_PARTIALLY_SPECIFIED)) - go_ahead = 1; - else - go_ahead = 0; + break; + } - if (go_ahead) { -#ifndef NO_USE_SOCKETS - if ((la->packetAliasMode & PKT_ALIAS_USE_SOCKETS) - && (lnk->flags & LINK_PARTIALLY_SPECIFIED) - && ((lnk->link_type == LINK_TCP) || - (lnk->link_type == LINK_UDP))) { - if (GetSocket(la, port_net, &lnk->sockfd, lnk->link_type)) { - lnk->alias_port = port_net; - return (0); - } - } else { + if (i >= max_trials) { +#ifdef LIBALIAS_DEBUG + fprintf(stderr, "PacketAlias/GetNewPort(): "); + fprintf(stderr, "could not find free port\n"); #endif - lnk->alias_port = port_net; - return (0); + return (-1); + } + #ifndef NO_USE_SOCKETS - } -#endif - } - if (la->aliasPortLower) { - port_sys = la->aliasPortLower + - (arc4random() % la->aliasPortLength); - port_net = htons(port_sys); - } else { - port_sys = arc4random() & ALIAS_PORT_MASK; - port_sys += ALIAS_PORT_BASE; - port_net = htons(port_sys); + if ((la->packetAliasMode & PKT_ALIAS_USE_SOCKETS) && + (lnk->flags & LINK_PARTIALLY_SPECIFIED) && + ((lnk->link_type == LINK_TCP) || + (lnk->link_type == LINK_UDP))) { + if (!GetSocket(la, port, &lnk->sockfd, lnk->link_type)) { + return (-1); } } - -#ifdef LIBALIAS_DEBUG - fprintf(stderr, "PacketAlias/GetNewPort(): "); - fprintf(stderr, "could not find free port\n"); #endif + lnk->alias_port = port; - return (-1); + return (0); } #ifndef NO_USE_SOCKETS @@ -760,7 +743,7 @@ FindNewPortGroup(struct libalias *la, { int i, j; int max_trials; - u_short port_sys; + u_short port; int link_type; LIBALIAS_LOCK_ASSERT(la); @@ -792,39 +775,31 @@ FindNewPortGroup(struct libalias *la, * try will be the actual source port. If this is already * in use, the remainder of the trials will be random. */ - port_sys = ntohs(src_port); + port = src_port; } else { - /* First trial and all subsequent are random. */ - if (align == FIND_EVEN_ALIAS_BASE) - port_sys = arc4random() & ALIAS_PORT_MASK_EVEN; - else - port_sys = arc4random() & ALIAS_PORT_MASK; - - port_sys += ALIAS_PORT_BASE; + port = _RandomPort(la); } /* Port number search */ - for (i = 0; i < max_trials; i++) { + for (i = 0; i < max_trials; i++, port = _RandomPort(la)) { struct alias_link *search_result; - for (j = 0; j < port_count; j++) + if (align) + port &= htons(0xfffe); + + for (j = 0; j < port_count; j++) { + u_short port_j = ntohs(port) + j; + if ((search_result = FindLinkIn(la, dst_addr, - alias_addr, dst_port, htons(port_sys + j), + alias_addr, dst_port, htons(port_j), link_type, 0)) != NULL) break; + } /* Found a good range, return base */ if (j == port_count) - return (htons(port_sys)); - - /* Find a new base to try */ - if (align == FIND_EVEN_ALIAS_BASE) - port_sys = arc4random() & ALIAS_PORT_MASK_EVEN; - else - port_sys = arc4random() & ALIAS_PORT_MASK; - - port_sys += ALIAS_PORT_BASE; + return (port); } #ifdef LIBALIAS_DEBUG @@ -2555,6 +2530,8 @@ LibAliasInit(struct libalias *la) la->aliasAddress.s_addr = INADDR_ANY; la->targetAddress.s_addr = INADDR_ANY; + la->aliasPortLower = 0x8000; + la->aliasPortLength = 0x8000; la->icmpLinkCount = 0; la->udpLinkCount = 0; _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/dev-commits-src-main To unsubscribe, send any mail to "[email protected]"
