svn commit: r248552 - in head: sbin/ipfw sys/netinet sys/netpfil/ipfw
Alexander V. Chernikov
melifaro at FreeBSD.org
Wed Mar 20 10:35:35 UTC 2013
Author: melifaro
Date: Wed Mar 20 10:35:33 2013
New Revision: 248552
URL: http://svnweb.freebsd.org/changeset/base/248552
Log:
Add ipfw support for setting/matching DiffServ codepoints (DSCP).
Setting DSCP support is done via O_SETDSCP which works for both
IPv4 and IPv6 packets. Fast checksum recalculation (RFC 1624) is done for IPv4.
Dscp can be specified by name (AFXY, CSX, BE, EF), by value
(0..63) or via tablearg.
Matching DSCP is done via another opcode (O_DSCP) which accepts several
classes at once (af11,af22,be). Classes are stored in bitmask (2 u32 words).
Many people made their variants of this patch, the ones I'm aware of are
(in alphabetic order):
Dmitrii Tejblum
Marcelo Araujo
Roman Bogorodskiy (novel)
Sergey Matveichuk (sem)
Sergey Ryabin
PR: kern/102471, kern/121122
MFC after: 2 weeks
Modified:
head/sbin/ipfw/ipfw.8
head/sbin/ipfw/ipfw2.c
head/sbin/ipfw/ipfw2.h
head/sys/netinet/ip_fw.h
head/sys/netpfil/ipfw/ip_fw2.c
head/sys/netpfil/ipfw/ip_fw_log.c
head/sys/netpfil/ipfw/ip_fw_sockopt.c
Modified: head/sbin/ipfw/ipfw.8
==============================================================================
--- head/sbin/ipfw/ipfw.8 Wed Mar 20 09:56:20 2013 (r248551)
+++ head/sbin/ipfw/ipfw.8 Wed Mar 20 10:35:33 2013 (r248552)
@@ -960,6 +960,61 @@ It is possible to use the
keyword with setfib.
If the tablearg value is not within the compiled range of fibs,
the packet's fib is set to 0.
+.It Cm setdscp Ar DSCP | number | tablearg
+Set specified DiffServ codepoint for an IPv4/IPv6 packet.
+Processing continues at the next rule.
+Supported values are:
+.Pp
+.Cm CS0
+.Pq Dv 000000 ,
+.Cm CS1
+.Pq Dv 001000 ,
+.Cm CS2
+.Pq Dv 010000 ,
+.Cm CS3
+.Pq Dv 011000 ,
+.Cm CS4
+.Pq Dv 100000 ,
+.Cm CS5
+.Pq Dv 101000 ,
+.Cm CS6
+.Pq Dv 110000 ,
+.Cm CS7
+.Pq Dv 111000 ,
+.Cm AF11
+.Pq Dv 001010 ,
+.Cm AF12
+.Pq Dv 001100 ,
+.Cm AF13
+.Pq Dv 001110 ,
+.Cm AF21
+.Pq Dv 010010 ,
+.Cm AF22
+.Pq Dv 010100 ,
+.Cm AF23
+.Pq Dv 010110 ,
+.Cm AF31
+.Pq Dv 011010 ,
+.Cm AF32
+.Pq Dv 011100 ,
+.Cm AF33
+.Pq Dv 011110 ,
+.Cm AF41
+.Pq Dv 100010 ,
+.Cm AF42
+.Pq Dv 100100 ,
+.Cm AF43
+.Pq Dv 100110 ,
+.Cm EF
+.Pq Dv 101110 ,
+.Cm BE
+.Pq Dv 000000 .
+Additionally, DSCP value can be specified by number (0..64).
+It is also possible to use the
+.Cm tablearg
+keyword with setdscp.
+If the tablearg value is not within the 0..64 range, lower 6 bits of supplied
+value are used.
.It Cm reass
Queue and reassemble IP fragments.
If the packet is not fragmented, counters are updated and
@@ -1454,6 +1509,17 @@ The supported IP types of service are:
The absence of a particular type may be denoted
with a
.Ql \&! .
+.It Cm dscp spec Ns Op , Ns Ar spec
+Matches IPv4/IPv6 packets whose
+.Cm DS
+field value is contained in
+.Ar spec
+mask.
+Multiple values can be specified via
+the comma separated list.
+Value can be one of keywords used in
+.Cm setdscp
+action or exact number.
.It Cm ipttl Ar ttl-list
Matches IPv4 packets whose time to live is included in
.Ar ttl-list ,
@@ -2976,6 +3042,23 @@ configured on
but coming in on
.Li fxp1
would be dropped.
+.Pp
+The
+.Cm setdscp
+option could be used to (re)mark user traffic,
+by adding the following to the appropriate place in ruleset:
+.Pp
+.Dl "ipfw add setdscp be ip from any to any dscp af11,af21"
+.Pp
+This rule drops all incoming packets that appear to be coming from another
+directly connected system but on the wrong interface.
+For example, a packet with a source address of
+.Li 192.168.0.0/24 ,
+configured on
+.Li fxp0 ,
+but coming in on
+.Li fxp1
+would be dropped.
.Ss DYNAMIC RULES
In order to protect a site from flood attacks involving fake
TCP packets, it is safer to use dynamic rules:
Modified: head/sbin/ipfw/ipfw2.c
==============================================================================
--- head/sbin/ipfw/ipfw2.c Wed Mar 20 09:56:20 2013 (r248551)
+++ head/sbin/ipfw/ipfw2.c Wed Mar 20 10:35:33 2013 (r248552)
@@ -167,6 +167,32 @@ static struct _s_x f_iptos[] = {
{ NULL, 0 }
};
+static struct _s_x f_ipdscp[] = {
+ { "af11", IPTOS_DSCP_AF11 >> 2 }, /* 001010 */
+ { "af12", IPTOS_DSCP_AF12 >> 2 }, /* 001100 */
+ { "af13", IPTOS_DSCP_AF13 >> 2 }, /* 001110 */
+ { "af21", IPTOS_DSCP_AF21 >> 2 }, /* 010010 */
+ { "af22", IPTOS_DSCP_AF22 >> 2 }, /* 010100 */
+ { "af23", IPTOS_DSCP_AF23 >> 2 }, /* 010110 */
+ { "af31", IPTOS_DSCP_AF31 >> 2 }, /* 011010 */
+ { "af32", IPTOS_DSCP_AF32 >> 2 }, /* 011100 */
+ { "af33", IPTOS_DSCP_AF33 >> 2 }, /* 011110 */
+ { "af41", IPTOS_DSCP_AF41 >> 2 }, /* 100010 */
+ { "af42", IPTOS_DSCP_AF42 >> 2 }, /* 100100 */
+ { "af43", IPTOS_DSCP_AF43 >> 2 }, /* 100110 */
+ { "be", IPTOS_DSCP_CS0 >> 2 }, /* 000000 */
+ { "ef", IPTOS_DSCP_EF >> 2 }, /* 101110 */
+ { "cs0", IPTOS_DSCP_CS0 >> 2 }, /* 000000 */
+ { "cs1", IPTOS_DSCP_CS1 >> 2 }, /* 001000 */
+ { "cs2", IPTOS_DSCP_CS2 >> 2 }, /* 010000 */
+ { "cs3", IPTOS_DSCP_CS3 >> 2 }, /* 011000 */
+ { "cs4", IPTOS_DSCP_CS4 >> 2 }, /* 100000 */
+ { "cs5", IPTOS_DSCP_CS5 >> 2 }, /* 101000 */
+ { "cs6", IPTOS_DSCP_CS6 >> 2 }, /* 110000 */
+ { "cs7", IPTOS_DSCP_CS7 >> 2 }, /* 100000 */
+ { NULL, 0 }
+};
+
static struct _s_x limit_masks[] = {
{"all", DYN_SRC_ADDR|DYN_SRC_PORT|DYN_DST_ADDR|DYN_DST_PORT},
{"src-addr", DYN_SRC_ADDR},
@@ -237,6 +263,7 @@ static struct _s_x rule_actions[] = {
{ "nat", TOK_NAT },
{ "reass", TOK_REASS },
{ "setfib", TOK_SETFIB },
+ { "setdscp", TOK_SETDSCP },
{ "call", TOK_CALL },
{ "return", TOK_RETURN },
{ NULL, 0 } /* terminator */
@@ -714,6 +741,51 @@ fill_newports(ipfw_insn_u16 *cmd, char *
return (i);
}
+/*
+ * Fill the body of the command with the list of DiffServ codepoints.
+ */
+static void
+fill_dscp(ipfw_insn *cmd, char *av, int cblen)
+{
+ uint32_t *low, *high;
+ char *s = av, *a;
+ int code;
+
+ cmd->opcode = O_DSCP;
+ cmd->len |= F_INSN_SIZE(ipfw_insn_u32) + 1;
+
+ CHECK_CMDLEN;
+
+ low = (uint32_t *)(cmd + 1);
+ high = low + 1;
+
+ *low = 0;
+ *high = 0;
+
+ while (s != NULL) {
+ a = strchr(s, ',');
+
+ if (a != NULL)
+ *a++ = '\0';
+
+ if (isalpha(*s)) {
+ if ((code = match_token(f_ipdscp, s)) == -1)
+ errx(EX_DATAERR, "Unknown DSCP code");
+ } else {
+ code = strtoul(s, NULL, 10);
+ if (code < 0 || code > 63)
+ errx(EX_DATAERR, "Invalid DSCP value");
+ }
+
+ if (code > 32)
+ *high |= 1 << (code - 32);
+ else
+ *low |= 1 << code;
+
+ s = a;
+ }
+}
+
static struct _s_x icmpcodes[] = {
{ "net", ICMP_UNREACH_NET },
{ "host", ICMP_UNREACH_HOST },
@@ -972,6 +1044,32 @@ print_icmptypes(ipfw_insn_u32 *cmd)
}
}
+static void
+print_dscp(ipfw_insn_u32 *cmd)
+{
+ int i, c;
+ uint32_t *v;
+ char sep= ' ';
+ const char *code;
+
+ printf(" dscp");
+ i = 0;
+ c = 0;
+ v = cmd->d;
+ while (i < 64) {
+ if (*v & (1 << i)) {
+ if ((code = match_value(f_ipdscp, i)) != NULL)
+ printf("%c%s", sep, code);
+ else
+ printf("%c%d", sep, i);
+ sep = ',';
+ }
+
+ if ((++i % 32) == 0)
+ v++;
+ }
+}
+
/*
* show_ipfw() prints the body of an ipfw rule.
* Because the standard rule has at least proto src_ip dst_ip, we use
@@ -1205,6 +1303,17 @@ show_ipfw(struct ip_fw *rule, int pcwidt
PRINT_UINT_ARG("setfib ", cmd->arg1);
break;
+ case O_SETDSCP:
+ {
+ const char *code;
+
+ if ((code = match_value(f_ipdscp, cmd->arg1)) != NULL)
+ printf("setdscp %s", code);
+ else
+ PRINT_UINT_ARG("setdscp ", cmd->arg1);
+ }
+ break;
+
case O_REASS:
printf("reass");
break;
@@ -1500,6 +1609,10 @@ show_ipfw(struct ip_fw *rule, int pcwidt
printf(" ipprecedence %u", (cmd->arg1) >> 5 );
break;
+ case O_DSCP:
+ print_dscp((ipfw_insn_u32 *)cmd);
+ break;
+
case O_IPLEN:
if (F_LEN(cmd) == 1)
printf(" iplen %u", cmd->arg1 );
@@ -3036,6 +3149,24 @@ chkarg:
break;
}
+ case TOK_SETDSCP:
+ {
+ int code;
+
+ action->opcode = O_SETDSCP;
+ NEED1("missing DSCP code");
+ if (_substrcmp(*av, "tablearg") == 0) {
+ action->arg1 = IP_FW_TABLEARG;
+ } else if (isalpha(*av[0])) {
+ if ((code = match_token(f_ipdscp, *av)) == -1)
+ errx(EX_DATAERR, "Unknown DSCP code");
+ action->arg1 = code;
+ } else
+ action->arg1 = strtoul(*av, NULL, 10);
+ av++;
+ break;
+ }
+
case TOK_REASS:
action->opcode = O_REASS;
break;
@@ -3448,6 +3579,12 @@ read_options:
av++;
break;
+ case TOK_DSCP:
+ NEED1("missing DSCP code");
+ fill_dscp(cmd, *av, cblen);
+ av++;
+ break;
+
case TOK_IPOPTS:
NEED1("missing argument for ipoptions");
fill_flags(cmd, O_IPOPT, f_ipopts, *av);
Modified: head/sbin/ipfw/ipfw2.h
==============================================================================
--- head/sbin/ipfw/ipfw2.h Wed Mar 20 09:56:20 2013 (r248551)
+++ head/sbin/ipfw/ipfw2.h Wed Mar 20 10:35:33 2013 (r248552)
@@ -203,6 +203,7 @@ enum tokens {
TOK_SETFIB,
TOK_LOOKUP,
TOK_SOCKARG,
+ TOK_SETDSCP,
};
/*
* the following macro returns an error message if we run out of
Modified: head/sys/netinet/ip_fw.h
==============================================================================
--- head/sys/netinet/ip_fw.h Wed Mar 20 09:56:20 2013 (r248551)
+++ head/sys/netinet/ip_fw.h Wed Mar 20 10:35:33 2013 (r248552)
@@ -218,6 +218,9 @@ enum ipfw_opcodes { /* arguments (4 byt
O_FORWARD_IP6, /* fwd sockaddr_in6 */
+ O_DSCP, /* 2 u32 = DSCP mask */
+ O_SETDSCP, /* arg1=DSCP value */
+
O_LAST_OPCODE /* not an opcode! */
};
Modified: head/sys/netpfil/ipfw/ip_fw2.c
==============================================================================
--- head/sys/netpfil/ipfw/ip_fw2.c Wed Mar 20 09:56:20 2013 (r248551)
+++ head/sys/netpfil/ipfw/ip_fw2.c Wed Mar 20 10:35:33 2013 (r248552)
@@ -1624,6 +1624,32 @@ do { \
flags_match(cmd, ip->ip_tos));
break;
+ case O_DSCP:
+ {
+ uint32_t *p;
+ uint16_t x;
+
+ p = ((ipfw_insn_u32 *)cmd)->d;
+
+ if (is_ipv4)
+ x = ip->ip_tos >> 2;
+ else if (is_ipv6) {
+ uint8_t *v;
+ v = &((struct ip6_hdr *)ip)->ip6_vfc;
+ x = (*v & 0x0F) << 2;
+ v++;
+ x |= *v >> 6;
+ } else
+ break;
+
+ /* DSCP bitmask is stored as low_u32 high_u32 */
+ if (x > 32)
+ match = *(p + 1) & (1 << (x - 32));
+ else
+ match = *p & (1 << x);
+ }
+ break;
+
case O_TCPDATALEN:
if (proto == IPPROTO_TCP && offset == 0) {
struct tcphdr *tcp;
@@ -2353,6 +2379,32 @@ do { \
break;
}
+ case O_SETDSCP: {
+ uint16_t code;
+
+ code = IP_FW_ARG_TABLEARG(cmd->arg1) & 0x3F;
+ l = 0; /* exit inner loop */
+ if (is_ipv4) {
+ uint16_t a;
+
+ a = ip->ip_tos;
+ ip->ip_tos = (code << 2) | (ip->ip_tos & 0x03);
+ a += ntohs(ip->ip_sum) - ip->ip_tos;
+ ip->ip_sum = htons(a);
+ } else if (is_ipv6) {
+ uint8_t *v;
+
+ v = &((struct ip6_hdr *)ip)->ip6_vfc;
+ *v = (*v & 0xF0) | (code >> 2);
+ v++;
+ *v = (*v & 0x3F) | ((code & 0x03) << 6);
+ } else
+ break;
+
+ IPFW_INC_RULE_COUNTER(f, pktlen);
+ break;
+ }
+
case O_NAT:
if (!IPFW_NAT_LOADED) {
retval = IP_FW_DENY;
Modified: head/sys/netpfil/ipfw/ip_fw_log.c
==============================================================================
--- head/sys/netpfil/ipfw/ip_fw_log.c Wed Mar 20 09:56:20 2013 (r248551)
+++ head/sys/netpfil/ipfw/ip_fw_log.c Wed Mar 20 10:35:33 2013 (r248552)
@@ -292,10 +292,8 @@ ipfw_log(struct ip_fw *f, u_int hlen, st
altq->qid);
cmd += F_LEN(cmd);
}
- if (cmd->opcode == O_PROB)
- cmd += F_LEN(cmd);
-
- if (cmd->opcode == O_TAG)
+ if (cmd->opcode == O_PROB || cmd->opcode == O_TAG ||
+ cmd->opcode == O_SETDSCP)
cmd += F_LEN(cmd);
action = action2;
Modified: head/sys/netpfil/ipfw/ip_fw_sockopt.c
==============================================================================
--- head/sys/netpfil/ipfw/ip_fw_sockopt.c Wed Mar 20 09:56:20 2013 (r248551)
+++ head/sys/netpfil/ipfw/ip_fw_sockopt.c Wed Mar 20 10:35:33 2013 (r248552)
@@ -671,6 +671,10 @@ check_ipfw_struct(struct ip_fw *rule, in
case O_IPID:
case O_IPTTL:
case O_IPLEN:
+ case O_DSCP:
+ if (cmdlen != F_INSN_SIZE(ipfw_insn_u32) + 1)
+ goto bad_size;
+ break;
case O_TCPDATALEN:
case O_TCPWIN:
case O_TAGGED:
@@ -738,6 +742,7 @@ check_ipfw_struct(struct ip_fw *rule, in
case O_ACCEPT:
case O_DENY:
case O_REJECT:
+ case O_SETDSCP:
#ifdef INET6
case O_UNREACH6:
#endif
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