[ovs-dev] [bug10576 5/5] learn: Make it possible to parse "load" actions wider than 64 bits.
Ethan Jackson
ethan at nicira.com
Sat Apr 14 01:06:47 UTC 2012
Looks good,
I would think that bitwise_is_all_zeros() belongs in it's own patch
just line bitwise_one(), but I don't think it matters much.
Ethan
On Wed, Apr 11, 2012 at 17:15, Ben Pfaff <blp at nicira.com> wrote:
> The implementation of the "learn" action now properly implements
> specifications such as 0x20010db885a308d313198a2e03707348->NXM_NX_IPV6_DST
> but the parser used in ovs-ofctl and elsewhere could not generate such
> specifications. This commit adds that support.
>
> Signed-off-by: Ben Pfaff <blp at nicira.com>
> ---
> lib/learn.c | 91 +++++++++++++++++++++++++++++++++++++-------------------
> lib/util.c | 55 ++++++++++++++++++++++++++++++++++
> lib/util.h | 2 +
> tests/learn.at | 9 ++++--
> 4 files changed, 123 insertions(+), 34 deletions(-)
>
> diff --git a/lib/learn.c b/lib/learn.c
> index d2db792..483442b 100644
> --- a/lib/learn.c
> +++ b/lib/learn.c
> @@ -317,13 +317,63 @@ struct learn_spec {
>
> int src_type;
> struct mf_subfield src;
> - uint8_t src_imm[sizeof(union mf_value)];
> + union mf_subvalue src_imm;
>
> int dst_type;
> struct mf_subfield dst;
> };
>
> static void
> +learn_parse_load_immediate(const char *s, struct learn_spec *spec)
> +{
> + const char *full_s = s;
> + const char *arrow = strstr(s, "->");
> + struct mf_subfield dst;
> + union mf_subvalue imm;
> +
> + memset(&imm, 0, sizeof imm);
> + if (s[0] == '0' && (s[1] == 'x' || s[1] == 'X') && arrow) {
> + const char *in = arrow - 1;
> + uint8_t *out = imm.u8 + sizeof imm.u8 - 1;
> + int n = arrow - (s + 2);
> + int i;
> +
> + for (i = 0; i < n; i++) {
> + int hexit = hexit_value(in[-i]);
> + if (hexit < 0) {
> + ovs_fatal(0, "%s: bad hex digit in value", full_s);
> + }
> + out[-(i / 2)] |= i % 2 ? hexit << 4 : hexit;
> + }
> + s = arrow;
> + } else {
> + imm.be64[1] = htonll(strtoull(s, (char **) &s, 0));
> + }
> +
> + if (strncmp(s, "->", 2)) {
> + ovs_fatal(0, "%s: missing `->' following value", full_s);
> + }
> + s += 2;
> +
> + s = mf_parse_subfield(&dst, s);
> + if (*s != '\0') {
> + ovs_fatal(0, "%s: trailing garbage following destination", full_s);
> + }
> +
> + if (!bitwise_is_all_zeros(&imm, sizeof imm, dst.n_bits,
> + (8 * sizeof imm) - dst.n_bits)) {
> + ovs_fatal(0, "%s: value does not fit into %u bits",
> + full_s, dst.n_bits);
> + }
> +
> + spec->n_bits = dst.n_bits;
> + spec->src_type = NX_LEARN_SRC_IMMEDIATE;
> + spec->src_imm = imm;
> + spec->dst_type = NX_LEARN_DST_LOAD;
> + spec->dst = dst;
> +}
> +
> +static void
> learn_parse_spec(const char *orig, char *name, char *value,
> struct learn_spec *spec)
> {
> @@ -340,7 +390,9 @@ learn_parse_spec(const char *orig, char *name, char *value,
>
> spec->n_bits = dst->n_bits;
> spec->src_type = NX_LEARN_SRC_IMMEDIATE;
> - memcpy(spec->src_imm, &imm, dst->n_bytes);
> + memset(&spec->src_imm, 0, sizeof spec->src_imm);
> + memcpy(&spec->src_imm.u8[sizeof spec->src_imm - dst->n_bytes],
> + &imm, dst->n_bytes);
> spec->dst_type = NX_LEARN_DST_MATCH;
> spec->dst.field = dst;
> spec->dst.ofs = 0;
> @@ -372,23 +424,7 @@ learn_parse_spec(const char *orig, char *name, char *value,
> spec->dst_type = NX_LEARN_DST_MATCH;
> } else if (!strcmp(name, "load")) {
> if (value[strcspn(value, "[-")] == '-') {
> - struct nx_action_reg_load load;
> - int nbits, imm_bytes;
> - uint64_t imm;
> - int i;
> -
> - nxm_parse_reg_load(&load, value);
> - nbits = nxm_decode_n_bits(load.ofs_nbits);
> - imm_bytes = DIV_ROUND_UP(nbits, 8);
> - imm = ntohll(load.value);
> -
> - spec->n_bits = nbits;
> - spec->src_type = NX_LEARN_SRC_IMMEDIATE;
> - for (i = 0; i < imm_bytes; i++) {
> - spec->src_imm[i] = imm >> ((imm_bytes - i - 1) * 8);
> - }
> - spec->dst_type = NX_LEARN_DST_LOAD;
> - nxm_decode(&spec->dst, load.dst, load.ofs_nbits);
> + learn_parse_load_immediate(value, spec);
> } else {
> struct nx_action_reg_move move;
>
> @@ -492,23 +528,16 @@ learn_parse(struct ofpbuf *b, char *arg, const struct flow *flow)
> /* Update 'rule' to allow for satisfying destination
> * prerequisites. */
> if (spec.src_type == NX_LEARN_SRC_IMMEDIATE
> - && spec.dst_type == NX_LEARN_DST_MATCH
> - && spec.dst.ofs == 0
> - && spec.n_bits == spec.dst.field->n_bytes * 8) {
> - union mf_value imm;
> -
> - memcpy(&imm, spec.src_imm, spec.dst.field->n_bytes);
> - mf_set_value(spec.dst.field, &imm, &rule);
> + && spec.dst_type == NX_LEARN_DST_MATCH) {
> + mf_write_subfield(&spec.dst, &spec.src_imm, &rule);
> }
>
> /* Output the flow_mod_spec. */
> put_u16(b, spec.n_bits | spec.src_type | spec.dst_type);
> if (spec.src_type == NX_LEARN_SRC_IMMEDIATE) {
> - int n_bytes = DIV_ROUND_UP(spec.n_bits, 8);
> - if (n_bytes % 2) {
> - ofpbuf_put_zeros(b, 1);
> - }
> - ofpbuf_put(b, spec.src_imm, n_bytes);
> + int n_bytes = DIV_ROUND_UP(spec.n_bits, 16) * 2;
> + int ofs = sizeof spec.src_imm - n_bytes;
> + ofpbuf_put(b, &spec.src_imm.u8[ofs], n_bytes);
> } else {
> put_u32(b, spec.src.field->nxm_header);
> put_u16(b, spec.src.ofs);
> diff --git a/lib/util.c b/lib/util.c
> index 14a97f2..72d0988 100644
> --- a/lib/util.c
> +++ b/lib/util.c
> @@ -913,6 +913,61 @@ bitwise_one(void *dst_, unsigned int dst_len, unsigned dst_ofs,
> }
> }
>
> +/* Scans the 'n_bits' bits starting from bit 'dst_ofs' in 'dst' for 1-bits.
> + * Returns false if any 1-bits are found, otherwise true. 'dst' is 'dst_len'
> + * bytes long.
> + *
> + * If you consider all of 'dst' to be a single unsigned integer in network byte
> + * order, then bit N is the bit with value 2**N. That is, bit 0 is the bit
> + * with value 1 in dst[dst_len - 1], bit 1 is the bit with value 2, bit 2 is
> + * the bit with value 4, ..., bit 8 is the bit with value 1 in dst[dst_len -
> + * 2], and so on.
> + *
> + * Required invariant:
> + * dst_ofs + n_bits <= dst_len * 8
> + */
> +bool
> +bitwise_is_all_zeros(const void *p_, unsigned int len, unsigned int ofs,
> + unsigned int n_bits)
> +{
> + const uint8_t *p = p_;
> +
> + if (!n_bits) {
> + return true;
> + }
> +
> + p += len - (ofs / 8 + 1);
> + ofs %= 8;
> +
> + if (ofs) {
> + unsigned int chunk = MIN(n_bits, 8 - ofs);
> +
> + if (*p & (((1 << chunk) - 1) << ofs)) {
> + return false;
> + }
> +
> + n_bits -= chunk;
> + if (!n_bits) {
> + return true;
> + }
> +
> + p--;
> + }
> +
> + while (n_bits >= 8) {
> + if (*p) {
> + return false;
> + }
> + n_bits -= 8;
> + }
> +
> + if (n_bits && *p & ((1 << n_bits) - 1)) {
> + return false;
> + }
> +
> + return true;
> +}
> +
> /* Copies the 'n_bits' low-order bits of 'value' into the 'n_bits' bits
> * starting at bit 'dst_ofs' in 'dst', which is 'dst_len' bytes long.
> *
> diff --git a/lib/util.h b/lib/util.h
> index 63f4a24..e5d1c3a 100644
> --- a/lib/util.h
> +++ b/lib/util.h
> @@ -230,6 +230,8 @@ void bitwise_zero(void *dst_, unsigned int dst_len, unsigned dst_ofs,
> unsigned int n_bits);
> void bitwise_one(void *dst_, unsigned int dst_len, unsigned dst_ofs,
> unsigned int n_bits);
> +bool bitwise_is_all_zeros(const void *, unsigned int len, unsigned int ofs,
> + unsigned int n_bits);
> void bitwise_put(uint64_t value,
> void *dst, unsigned int dst_len, unsigned int dst_ofs,
> unsigned int n_bits);
> diff --git a/tests/learn.at b/tests/learn.at
> index 8431937..0d1406c 100644
> --- a/tests/learn.at
> +++ b/tests/learn.at
> @@ -139,7 +139,9 @@ OVS_VSWITCHD_START(
> add-port br0 eth1 -- set Interface eth1 type=dummy -- \
> add-port br0 eth2 -- set Interface eth2 type=dummy])
> # Set up flow table for TCPv6 port learning.
> -AT_CHECK([[ovs-ofctl add-flow br0 'table=0 tcp6 actions=learn(table=1, hard_timeout=60, eth_type=0x86dd, nw_proto=6, NXM_NX_IPV6_SRC[]=NXM_NX_IPV6_DST[], NXM_NX_IPV6_DST[]=NXM_NX_IPV6_SRC[], NXM_OF_TCP_SRC[]=NXM_OF_TCP_DST[], NXM_OF_TCP_DST[]=NXM_OF_TCP_SRC[]), flood']])
> +# Also add a 128-bit-wide "load" action and a 128-bit literal match to check
> +# that they work.
> +AT_CHECK([[ovs-ofctl add-flow br0 'table=0 tcp6 actions=learn(table=1, hard_timeout=60, eth_type=0x86dd, nw_proto=6, NXM_NX_IPV6_SRC[]=NXM_NX_IPV6_DST[], ipv6_dst=2001:0db8:85a3:0000:0000:8a2e:0370:7334, NXM_OF_TCP_SRC[]=NXM_OF_TCP_DST[], NXM_OF_TCP_DST[]=NXM_OF_TCP_SRC[], load(0x20010db885a308d313198a2e03707348->NXM_NX_IPV6_DST[])), flood']])
>
> # Trace a TCPv6 packet arriving on port 3.
> AT_CHECK([ovs-appctl ofproto/trace br0 'in_port(3),eth(src=50:54:00:00:00:05,dst=50:54:00:00:00:06),eth_type(0x86dd),ipv6(src=fec0::2,dst=fec0::1,label=0,proto=6,tclass=0,hlimit=255,frag=no),tcp(src=40000,dst=80)' -generate], [0], [stdout])
> @@ -147,8 +149,9 @@ AT_CHECK([tail -1 stdout], [0], [Datapath actions: 2,0,1
> ])
>
> # Check for the learning entry.
> -AT_CHECK([ovs-ofctl dump-flows br0 table=1 | ofctl_strip | sort], [0], [dnl
> - table=1, hard_timeout=60,tcp6,ipv6_src=fec0::1,ipv6_dst=fec0::2,tp_src=80,tp_dst=40000 actions=drop
> +AT_CHECK([ovs-ofctl dump-flows br0 | ofctl_strip | sort], [0], [dnl
> + table=1, hard_timeout=60,tcp6,ipv6_src=fec0::1,ipv6_dst=2001:db8:85a3::8a2e:370:7334,tp_src=80,tp_dst=40000 actions=load:0x13198a2e03707348->NXM_NX_IPV6_DST[[0..63]],load:0x20010db885a308d3->NXM_NX_IPV6_DST[[64..127]]
> + tcp6 actions=learn(table=1,hard_timeout=60,eth_type=0x86dd,nw_proto=6,NXM_NX_IPV6_SRC[[]]=NXM_NX_IPV6_DST[[]],ipv6_dst=2001:db8:85a3::8a2e:370:7334,NXM_OF_TCP_SRC[[]]=NXM_OF_TCP_DST[[]],NXM_OF_TCP_DST[[]]=NXM_OF_TCP_SRC[[]],load:0x20010db885a308d313198a2e03707348->NXM_NX_IPV6_DST[[]]),FLOOD
> NXST_FLOW reply:
> ])
> OVS_VSWITCHD_STOP
> --
> 1.7.2.5
>
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