Date: Fri, 2 Sep 2016 21:14:29 +0000 (UTC) From: "Conrad E. Meyer" <cem@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r305306 - head/sbin/dhclient Message-ID: <201609022114.u82LETjU007369@repo.freebsd.org>
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Author: cem Date: Fri Sep 2 21:14:29 2016 New Revision: 305306 URL: https://svnweb.freebsd.org/changeset/base/305306 Log: dhclient: add support for interface-mtu (26) Make dhclient set interface MTU if it was provided. This version implements MTU setting in dhclient itself before it runs dhclient-script. PR: 206721 Submitted by: novel@ Reported by: Jarrod Petz <jlpetz at gmail.com> Reviewed by: cem, allanjude Differential Revision: https://reviews.freebsd.org/D5675 Modified: head/sbin/dhclient/clparse.c head/sbin/dhclient/dhclient.c head/sbin/dhclient/dhcpd.h head/sbin/dhclient/dispatch.c head/sbin/dhclient/privsep.c head/sbin/dhclient/privsep.h Modified: head/sbin/dhclient/clparse.c ============================================================================== --- head/sbin/dhclient/clparse.c Fri Sep 2 21:13:46 2016 (r305305) +++ head/sbin/dhclient/clparse.c Fri Sep 2 21:14:29 2016 (r305306) @@ -102,6 +102,8 @@ read_client_conf(void) [top_level_config.requested_option_count++] = DHO_HOST_NAME; top_level_config.requested_options [top_level_config.requested_option_count++] = DHO_DOMAIN_SEARCH; + top_level_config.requested_options + [top_level_config.requested_option_count++] = DHO_INTERFACE_MTU; if ((cfile = fopen(path_dhclient_conf, "r")) != NULL) { do { Modified: head/sbin/dhclient/dhclient.c ============================================================================== --- head/sbin/dhclient/dhclient.c Fri Sep 2 21:13:46 2016 (r305305) +++ head/sbin/dhclient/dhclient.c Fri Sep 2 21:14:29 2016 (r305306) @@ -60,6 +60,7 @@ __FBSDID("$FreeBSD$"); #include "privsep.h" #include <sys/capsicum.h> +#include <sys/endian.h> #include <net80211/ieee80211_freebsd.h> @@ -132,6 +133,9 @@ int fork_privchld(int, int); ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len)) +/* Minimum MTU is 68 as per RFC791, p. 24 */ +#define MIN_MTU 68 + static time_t scripttime; int @@ -798,9 +802,20 @@ dhcpack(struct packet *packet) void bind_lease(struct interface_info *ip) { + struct option_data *opt; + /* Remember the medium. */ ip->client->new->medium = ip->client->medium; + opt = &ip->client->new->options[DHO_INTERFACE_MTU]; + if (opt->len == sizeof(u_int16_t)) { + u_int16_t mtu = be16dec(opt->data); + if (mtu < MIN_MTU) + warning("mtu size %u < %d: ignored", (unsigned)mtu, MIN_MTU); + else + interface_set_mtu_unpriv(privfd, mtu); + } + /* Write out the new lease. */ write_client_lease(ip, ip->client->new, 0); Modified: head/sbin/dhclient/dhcpd.h ============================================================================== --- head/sbin/dhclient/dhcpd.h Fri Sep 2 21:13:46 2016 (r305305) +++ head/sbin/dhclient/dhcpd.h Fri Sep 2 21:14:29 2016 (r305306) @@ -319,6 +319,8 @@ void cancel_timeout(void (*)(void *), vo void add_protocol(char *, int, void (*)(struct protocol *), void *); void remove_protocol(struct protocol *); int interface_link_status(char *); +void interface_set_mtu_unpriv(int, u_int16_t); +void interface_set_mtu_priv(char *, u_int16_t); /* hash.c */ struct hash_table *new_hash(void); Modified: head/sbin/dhclient/dispatch.c ============================================================================== --- head/sbin/dhclient/dispatch.c Fri Sep 2 21:13:46 2016 (r305305) +++ head/sbin/dhclient/dispatch.c Fri Sep 2 21:14:29 2016 (r305306) @@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$"); #include "dhcpd.h" +#include "privsep.h" #include <sys/ioctl.h> @@ -501,3 +502,46 @@ interface_link_status(char *ifname) } return (1); } + +void +interface_set_mtu_unpriv(int privfd, u_int16_t mtu) +{ + struct imsg_hdr hdr; + struct buf *buf; + int errs = 0; + + hdr.code = IMSG_SET_INTERFACE_MTU; + hdr.len = sizeof(hdr) + + sizeof(u_int16_t); + + if ((buf = buf_open(hdr.len)) == NULL) + error("buf_open: %m"); + + errs += buf_add(buf, &hdr, sizeof(hdr)); + errs += buf_add(buf, &mtu, sizeof(mtu)); + if (errs) + error("buf_add: %m"); + + if (buf_close(privfd, buf) == -1) + error("buf_close: %m"); +} + +void +interface_set_mtu_priv(char *ifname, u_int16_t mtu) +{ + struct ifreq ifr; + int sock; + + if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) + error("Can't create socket"); + + memset(&ifr, 0, sizeof(ifr)); + + strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); + ifr.ifr_mtu = mtu; + + if (ioctl(sock, SIOCSIFMTU, &ifr) == -1) + warning("SIOCSIFMTU failed (%d): %s", mtu, + strerror(errno)); + close(sock); +} Modified: head/sbin/dhclient/privsep.c ============================================================================== --- head/sbin/dhclient/privsep.c Fri Sep 2 21:13:46 2016 (r305305) +++ head/sbin/dhclient/privsep.c Fri Sep 2 21:14:29 2016 (r305306) @@ -111,6 +111,7 @@ dispatch_imsg(struct interface_info *ifi struct client_lease lease; int ret, i, optlen; struct buf *buf; + u_int16_t mtu; buf_read(fd, &hdr, sizeof(hdr)); @@ -235,6 +236,13 @@ dispatch_imsg(struct interface_info *ifi case IMSG_SEND_PACKET: send_packet_priv(ifi, &hdr, fd); break; + case IMSG_SET_INTERFACE_MTU: + if (hdr.len < sizeof(hdr) + sizeof(u_int16_t)) + error("corrupted message received"); + + buf_read(fd, &mtu, sizeof(u_int16_t)); + interface_set_mtu_priv(ifi->name, mtu); + break; default: error("received unknown message, code %d", hdr.code); } Modified: head/sbin/dhclient/privsep.h ============================================================================== --- head/sbin/dhclient/privsep.h Fri Sep 2 21:13:46 2016 (r305305) +++ head/sbin/dhclient/privsep.h Fri Sep 2 21:14:29 2016 (r305306) @@ -36,7 +36,8 @@ enum imsg_code { IMSG_SCRIPT_WRITE_PARAMS, IMSG_SCRIPT_GO, IMSG_SCRIPT_GO_RET, - IMSG_SEND_PACKET + IMSG_SEND_PACKET, + IMSG_SET_INTERFACE_MTU, }; struct imsg_hdr {
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